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• Error compiling GLib in Ubuntu 14.04 (trying to install GimpShop)

  - by Nicolás Salvarrey

  I'm kinda new in Linux, so please take it easy on the most complicated stuff. I'm trying to install GimpShop. Installation guide asks me to install GLib first, and when I try to compile it using the make command I get errors. When I run the ./configure --prefix=/usr command, I get this: checking for a BSD-compatible install... /usr/bin/install -c checking whether build environment is sane... yes checking for gawk... no checking for mawk... mawk checking whether make sets $(MAKE)... yes checking whether to enable maintainer-specific portions of Makefiles... no checking build system type... x86_64-unknown-linux-gnu checking host system type... x86_64-unknown-linux-gnu checking for the BeOS... no checking for Win32... no checking whether to enable garbage collector friendliness... no checking whether to disable memory pools... no checking for gcc... gcc checking for C compiler default output file name... a.out checking whether the C compiler works... yes checking whether we are cross compiling... no checking for suffix of executables... checking for suffix of object files... o checking whether we are using the GNU C compiler... yes checking whether gcc accepts -g... yes checking for gcc option to accept ANSI C... none needed checking for style of include used by make... GNU checking dependency style of gcc... gcc3 checking for c++... no checking for g++... no checking for gcc... gcc checking whether we are using the GNU C++ compiler... no checking whether gcc accepts -g... no checking dependency style of gcc... gcc3 checking for gcc option to accept ANSI C... none needed checking for a BSD-compatible install... /usr/bin/install -c checking for special C compiler options needed for large files... no checking for _FILE_OFFSET_BITS value needed for large files... no checking for _LARGE_FILES value needed for large files... no checking for pkg-config... /usr/bin/pkg-config checking for gawk... (cached) mawk checking for perl5... no checking for perl... perl checking for indent... no checking for perl... /usr/bin/perl checking for iconv_open... yes checking how to run the C preprocessor... gcc -E checking for egrep... grep -E checking for ANSI C header files... yes checking for sys/types.h... yes checking for sys/stat.h... yes checking for stdlib.h... yes checking for string.h... yes checking for memory.h... yes checking for strings.h... yes checking for inttypes.h... yes checking for stdint.h... yes checking for unistd.h... yes checking locale.h usability... yes checking locale.h presence... yes checking for locale.h... yes checking for LC_MESSAGES... yes checking libintl.h usability... yes checking libintl.h presence... yes checking for libintl.h... yes checking for ngettext in libc... yes checking for dgettext in libc... yes checking for bind_textdomain_codeset... yes checking for msgfmt... /usr/bin/msgfmt checking for dcgettext... yes checking for gmsgfmt... /usr/bin/msgfmt checking for xgettext... /usr/bin/xgettext checking for catalogs to be installed... am ar az be bg bn bs ca cs cy da de el en_CA en_GB eo es et eu fa fi fr ga gl gu he hi hr id is it ja ko lt lv mk mn ms nb ne nl nn no or pa pl pt pt_BR ro ru sk sl sq sr sr@ije sr@Latn sv ta tl tr uk vi wa xh yi zh_CN zh_TW checking for a sed that does not truncate output... /bin/sed checking for ld used by gcc... /usr/bin/ld checking if the linker (/usr/bin/ld) is GNU ld... yes checking for /usr/bin/ld option to reload object files... -r checking for BSD-compatible nm... /usr/bin/nm -B checking whether ln -s works... yes checking how to recognise dependent libraries... pass_all checking dlfcn.h usability... yes checking dlfcn.h presence... yes checking for dlfcn.h... yes checking for g77... no checking for f77... no checking for xlf... no checking for frt... no checking for pgf77... no checking for fort77... no checking for fl32... no checking for af77... no checking for f90... no checking for xlf90... no checking for pgf90... no checking for epcf90... no checking for f95... no checking for fort... no checking for xlf95... no checking for ifc... no checking for efc... no checking for pgf95... no checking for lf95... no checking for gfortran... no checking whether we are using the GNU Fortran 77 compiler... no checking whether accepts -g... no checking the maximum length of command line arguments... 32768 checking command to parse /usr/bin/nm -B output from gcc object... ok checking for objdir... .libs checking for ar... ar checking for ranlib... ranlib checking for strip... strip checking if gcc static flag works... yes checking if gcc supports -fno-rtti -fno-exceptions... no checking for gcc option to produce PIC... -fPIC checking if gcc PIC flag -fPIC works... yes checking if gcc supports -c -o file.o... yes checking whether the gcc linker (/usr/bin/ld -m elf_x86_64) supports shared libraries... yes checking whether -lc should be explicitly linked in... no checking dynamic linker characteristics... GNU/Linux ld.so checking how to hardcode library paths into programs... immediate checking whether stripping libraries is possible... yes checking if libtool supports shared libraries... yes checking whether to build shared libraries... yes checking whether to build static libraries... no configure: creating libtool appending configuration tag "CXX" to libtool appending configuration tag "F77" to libtool checking for extra flags to get ANSI library prototypes... none needed checking for extra flags for POSIX compliance... none needed checking for ANSI C header files... (cached) yes checking for vprintf... yes checking for _doprnt... no checking for working alloca.h... yes checking for alloca... yes checking for atexit... yes checking for on_exit... yes checking for char... yes checking size of char... 1 checking for short... yes checking size of short... 2 checking for long... yes checking size of long... 8 checking for int... yes checking size of int... 4 checking for void *... yes checking size of void *... 8 checking for long long... yes checking size of long long... 8 checking for __int64... no checking size of __int64... 0 checking for format to printf and scanf a guint64... %llu checking for an ANSI C-conforming const... yes checking if malloc() and friends prototypes are gmem.h compatible... no checking for growing stack pointer... yes checking for __inline... yes checking for __inline__... yes checking for inline... yes checking if inline functions in headers work... yes checking for ISO C99 varargs macros in C... yes checking for ISO C99 varargs macros in C++... no checking for GNUC varargs macros... yes checking for GNUC visibility attribute... yes checking whether byte ordering is bigendian... no checking dirent.h usability... yes checking dirent.h presence... yes checking for dirent.h... yes checking float.h usability... yes checking float.h presence... yes checking for float.h... yes checking limits.h usability... yes checking limits.h presence... yes checking for limits.h... yes checking pwd.h usability... yes checking pwd.h presence... yes checking for pwd.h... yes checking sys/param.h usability... yes checking sys/param.h presence... yes checking for sys/param.h... yes checking sys/poll.h usability... yes checking sys/poll.h presence... yes checking for sys/poll.h... yes checking sys/select.h usability... yes checking sys/select.h presence... yes checking for sys/select.h... yes checking for sys/types.h... (cached) yes checking sys/time.h usability... yes checking sys/time.h presence... yes checking for sys/time.h... yes checking sys/times.h usability... yes checking sys/times.h presence... yes checking for sys/times.h... yes checking for unistd.h... (cached) yes checking values.h usability... yes checking values.h presence... yes checking for values.h... yes checking for stdint.h... (cached) yes checking sched.h usability... yes checking sched.h presence... yes checking for sched.h... yes checking langinfo.h usability... yes checking langinfo.h presence... yes checking for langinfo.h... yes checking for nl_langinfo... yes checking for nl_langinfo and CODESET... yes checking whether we are using the GNU C Library 2.1 or newer... yes checking stddef.h usability... yes checking stddef.h presence... yes checking for stddef.h... yes checking for stdlib.h... (cached) yes checking for string.h... (cached) yes checking for setlocale... yes checking for size_t... yes checking size of size_t... 8 checking for the appropriate definition for size_t... unsigned long checking for lstat... yes checking for strerror... yes checking for strsignal... yes checking for memmove... yes checking for mkstemp... yes checking for vsnprintf... yes checking for stpcpy... yes checking for strcasecmp... yes checking for strncasecmp... yes checking for poll... yes checking for getcwd... yes checking for nanosleep... yes checking for vasprintf... yes checking for setenv... yes checking for unsetenv... yes checking for getc_unlocked... yes checking for readlink... yes checking for symlink... yes checking for C99 vsnprintf... yes checking whether printf supports positional parameters... yes checking for signed... yes checking for long long... (cached) yes checking for long double... yes checking for wchar_t... yes checking for wint_t... yes checking for size_t... (cached) yes checking for ptrdiff_t... yes checking for inttypes.h... yes checking for stdint.h... yes checking for snprintf... yes checking for C99 snprintf... yes checking for sys_errlist... yes checking for sys_siglist... yes checking for sys_siglist declaration... yes checking for fd_set... yes, found in sys/types.h checking whether realloc (NULL,) will work... yes checking for nl_langinfo (CODESET)... yes checking for OpenBSD strlcpy/strlcat... no checking for an implementation of va_copy()... yes checking for an implementation of __va_copy()... yes checking whether va_lists can be copied by value... no checking for dlopen... no checking for NSLinkModule... no checking for dlopen in -ldl... yes checking for dlsym in -ldl... yes checking for RTLD_GLOBAL brokenness... no checking for preceeding underscore in symbols... no checking for dlerror... yes checking for the suffix of shared libraries... .so checking for gspawn implementation... gspawn.lo checking for GIOChannel implementation... giounix.lo checking for platform-dependent source... checking whether to compile timeloop... yes checking if building for some Win32 platform... no checking for thread implementation... posix checking thread related cflags... -pthread checking for sched_get_priority_min... yes checking thread related libraries... -pthread checking for localtime_r... yes checking for posix getpwuid_r... yes checking size of pthread_t... 8 checking for pthread_attr_setstacksize... yes checking for minimal/maximal thread priority... sched_get_priority_min(SCHED_OTHER)/sched_get_priority_max(SCHED_OTHER) checking for pthread_setschedparam... yes checking for posix yield function... sched_yield checking size of pthread_mutex_t... 40 checking byte contents of PTHREAD_MUTEX_INITIALIZER... 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 checking whether to use assembler code for atomic operations... x86_64 checking value of POLLIN... 1 checking value of POLLOUT... 4 checking value of POLLPRI... 2 checking value of POLLERR... 8 checking value of POLLHUP... 16 checking value of POLLNVAL... 32 checking for EILSEQ... yes configure: creating ./config.status config.status: creating glib-2.0.pc config.status: creating glib-2.0-uninstalled.pc config.status: creating gmodule-2.0.pc config.status: creating gmodule-no-export-2.0.pc config.status: creating gmodule-2.0-uninstalled.pc config.status: creating gthread-2.0.pc config.status: creating gthread-2.0-uninstalled.pc config.status: creating gobject-2.0.pc config.status: creating gobject-2.0-uninstalled.pc config.status: creating glib-zip config.status: creating glib-gettextize config.status: creating Makefile config.status: creating build/Makefile config.status: creating build/win32/Makefile config.status: creating build/win32/dirent/Makefile config.status: creating glib/Makefile config.status: creating glib/libcharset/Makefile config.status: creating glib/gnulib/Makefile config.status: creating gmodule/Makefile config.status: creating gmodule/gmoduleconf.h config.status: creating gobject/Makefile config.status: creating gobject/glib-mkenums config.status: creating gthread/Makefile config.status: creating po/Makefile.in config.status: creating docs/Makefile config.status: creating docs/reference/Makefile config.status: creating docs/reference/glib/Makefile config.status: creating docs/reference/glib/version.xml config.status: creating docs/reference/gobject/Makefile config.status: creating docs/reference/gobject/version.xml config.status: creating tests/Makefile config.status: creating tests/gobject/Makefile config.status: creating m4macros/Makefile config.status: creating config.h config.status: config.h is unchanged config.status: executing depfiles commands config.status: executing default-1 commands config.status: executing glibconfig.h commands config.status: glibconfig.h is unchanged config.status: executing chmod-scripts commands nsalvarrey@Delleuze:~/glib-2.6.3$ ^C nsalvarrey@Delleuze:~/glib-2.6.3$ And then, with the make command, I get this: galias.h:83:39: error: 'g_ascii_digit_value' aliased to undefined symbol 'IA__g_ascii_digit_value' extern __typeof (g_ascii_digit_value) g_ascii_digit_value __attribute((alias("IA__g_ascii_digit_value"), visibility("default"))); ^ In file included from garray.c:35:0: galias.h:31:35: error: 'g_allocator_new' aliased to undefined symbol 'IA__g_allocator_new' extern __typeof (g_allocator_new) g_allocator_new __attribute((alias("IA__g_allocator_new"), visibility("default"))); ^ make[4]: *** [garray.lo] Error 1 make[4]: se sale del directorio «/home/nsalvarrey/glib-2.6.3/glib» make[3]: *** [all-recursive] Error 1 make[3]: se sale del directorio «/home/nsalvarrey/glib-2.6.3/glib» make[2]: *** [all] Error 2 make[2]: se sale del directorio «/home/nsalvarrey/glib-2.6.3/glib» make[1]: *** [all-recursive] Error 1 make[1]: se sale del directorio «/home/nsalvarrey/glib-2.6.3» make: *** [all] Error 2 nsalvarrey@Delleuze:~/glib-2.6.3$ (it's actually a lot longer) Can somebody help me?

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• iPhone SDK vs. Windows Phone 7 Series SDK Challenge, Part 2: MoveMe

  In this series, I will be taking sample applications from the iPhone SDK and implementing them on Windows Phone 7 Series.  My goal is to do as much of an apples-to-apples comparison as I can.  This series will be written to not only compare and contrast how easy or difficult it is to complete tasks on either platform, how many lines of code, etc., but Id also like it to be a way for iPhone developers to either get started on Windows Phone 7 Series development, or for developers in general to learn the platform. Heres my methodology: Run the iPhone SDK app in the iPhone Simulator to get a feel for what it does and how it works, without looking at the implementation Implement the equivalent functionality on Windows Phone 7 Series using Silverlight. Compare the two implementations based on complexity, functionality, lines of code, number of files, etc. Add some functionality to the Windows Phone 7 Series app that shows off a way to make the scenario more interesting or leverages an aspect of the platform, or uses a better design pattern to implement the functionality. You can download Microsoft Visual Studio 2010 Express for Windows Phone CTP here, and the Expression Blend 4 Beta here. If youre seeing this series for the first time, check out Part 1: Hello World. A note on methodologyin the prior post there was some feedback about lines of code not being a very good metric for this exercise.  I dont really disagree, theres a lot more to this than lines of code but I believe that is a relevant metric, even if its not the ultimate one.  And theres no perfect answer here.  So I am going to continue to report the number of lines of code that I, as a developer would need to write in these apps as a data point, and Ill leave it up to the reader to determine how that fits in with overall complexity, etc.  The first example was so basic that I think it was difficult to talk about in real terms.  I think that as these apps get more complex, the subjective differences in concept count and will be more important.  MoveMe The MoveMe app is the main end-to-end app writing example in the iPhone SDK, called Creating an iPhone Application.  This application demonstrates a few concepts, including handling touch input, how to do animations, and how to do some basic transforms. The behavior of the application is pretty simple.  User touches the button: The button does a throb type animation where it scales up and then back down briefly. User drags the button: After a touch begins, moving the touch point will drag the button around with the touch. User lets go of the button: The button animates back to its original position, but does a few small bounces as it reaches its original point, which makes the app fun and gives it an extra bit of interactivity. Now, how would I write an app that meets this spec for Windows Phone 7 Series, and how hard would it be?  Lets find out!     Implementing the UI Okay, lets build the UI for this application.  In the HelloWorld example, we did all the UI design in Visual Studio and/or by hand in XAML.  In this example, were going to use the Expression Blend 4 Beta. You might be wondering when to use Visual Studio, when to use Blend, and when to do XAML by hand.  Different people will have different takes on this, but heres mine: XAML by hand simple UI that doesnt contain animations, gradients, etc., and or UI that I want to really optimize and craft when I know exactly what I want to do. Visual Studio Basic UI layout, property setting, data binding, etc. Blend Any serious design work needs to be done in Blend, including animations, handling states and transitions, styling and templating, editing resources. As in Part 1, go ahead and fire up Visual Studio 2010 Express for Windows Phone (yes, soon it will take longer to say the name of our products than to start them up!), and create a new Windows Phone Application.  As in Part 1, clear out the XAML from the designer.  An easy way to do this is to just: Click on the design surface Hit Control+A Hit Delete Theres a little bit left over (the Grid.RowDefinitions element), just go ahead and delete that element so were starting with a clean state of only one outer Grid element. To use Blend, we need to save this project.  See, when you create a project with Visual Studio Express, it doesnt commit it to the disk (well, in a place where you can find it, at least) until you actually save the project.  This is handy if youre doing some fooling around, because it doesnt clutter your disk with WindowsPhoneApplication23-like directories.  But its also kind of dangerous, since when you close VS, if you dont save the projectits all gone.  Yes, this has bitten me since I was saving files and didnt remember that, so be careful to save the project/solution via Save All, at least once. So, save and note the location on disk.  Start Expression Blend 4 Beta, and chose File > Open Project/Solution, and load your project.  You should see just about the same thing you saw over in VS: a blank, black designer surface. Now, thinking about this application, we dont really need a button, even though it looks like one.  We never click it.  So were just going to create a visual and use that.  This is also true in the iPhone example above, where the visual is actually not a button either but a jpg image with a nice gradient and round edges.  Well do something simple here that looks pretty good. In Blend, look in the tool pane on the left for the icon that looks like the below (the highlighted one on the left), and hold it down to get the popout menu, and choose Border:    Okay, now draw out a box in the middle of the design surface of about 300x100.  The Properties Pane to the left should show the properties for this item. First, lets make it more visible by giving it a border brush.  Set the BorderBrush to white by clicking BorderBrush and dragging the color selector all the way to the upper right in the palette.  Then, down a bit farther, make the BorderThickness 4 all the way around, and the CornerRadius set to 6. In the Layout section, do the following to Width, Height, Horizontal and Vertical Alignment, and Margin (all 4 margin values): Youll see the outline now is in the middle of the design surface.  Now lets give it a background color.  Above BorderBrush select Background, and click the third tab over: Gradient Brush.  Youll see a gradient slider at the bottom, and if you click the markers, you can edit the gradient stops individually (or add more).  In this case, you can select something you like, but wheres what I chose: Left stop: #BFACCFE2 (I just picked a spot on the palette and set opacity to 75%, no magic here, feel free to fiddle these or just enter these numbers into the hex area and be done with it) Right stop: #FF3E738F Okay, looks pretty good.  Finally set the name of the element in the Name field at the top of the Properties pane to welcome. Now lets add some text.  Just hit T and itll select the TextBlock tool automatically: Now draw out some are inside our welcome visual and type Welcome!, then click on the design surface (to exit text entry mode) and hit V to go back into selection mode (or the top item in the tool pane that looks like a mouse pointer).  Click on the text again to select it in the tool pane.  Just like the border, we want to center this.  So set HorizontalAlignment and VerticalAlignment to Center, and clear the Margins: Thats it for the UI.  Heres how it looks, on the design surface: Not bad!  Okay, now the fun part Adding Animations Using Blend to build animations is a lot of fun, and its easy.  In XAML, I can not only declare elements and visuals, but also I can declare animations that will affect those visuals.  These are called Storyboards. To recap, well be doing two animations: The throb animation when the element is touched The center animation when the element is released after being dragged. The throb animation is just a scale transform, so well do that first.  In the Objects and Timeline Pane (left side, bottom half), click the little + icon to add a new Storyboard called touchStoryboard: The timeline view will appear.  In there, click a bit to the right of 0 to create a keyframe at .2 seconds: Now, click on our welcome element (the Border, not the TextBlock in it), and scroll to the bottom of the Properties Pane.  Open up Transform, click the third tab ("Scale), and set X and Y to 1.2: This all of this says that, at .2 seconds, I want the X and Y size of this element to scale to 1.2. In fact you can see this happen.  Push the Play arrow in the timeline view, and youll see the animation run! Lets make two tweaks.  First, we want the animation to automatically reverse so it scales up then back down nicely. Click in the dropdown that says touchStoryboard in Objects and Timeline, then in the Properties pane check Auto Reverse: Now run it again, and youll see it go both ways. Lets even make it nicer by adding an easing function. First, click on the Render Transform item in the Objects tree, then, in the Property Pane, youll see a bunch of easing functions to choose from.  Feel free to play with this, then seeing how each runs.  I chose Circle In, but some other ones are fun.  Try them out!  Elastic In is kind of fun, but well stick with Circle In.  Thats it for that animation. Now, we also want an animation to move the Border back to its original position when the user ends the touch gesture.  This is exactly the same process as above, but just targeting a different transform property. Create a new animation called releaseStoryboard Select a timeline point at 1.2 seconds. Click on the welcome Border element again Scroll to the Transforms panel at the bottom of the Properties Pane Choose the first tab (Translate), which may already be selected Set both X and Y values to 0.0 (we do this just to make the values stick, because the value is already 0 and we need Blend to know we want to save that value) Click on RenderTransform in the Objects tree In the properties pane, choose Bounce Out Set Bounces to 6, and Bounciness to 4 (feel free to play with these as well) Okay, were done. Note, if you want to test this Storyboard, you have to do something a little tricky because the final value is the same as the initial value, so playing it does nothing.  If you want to play with it, do the following: Next to the selection dropdown, hit the little "x (Close Storyboard) Go to the Translate Transform value for welcome Set X,Y to 50, 200, respectively (or whatever) Select releaseStoryboard again from the dropdown Hit play, see it run Go into the object tree and select RenderTransform to change the easing function. When youre done, hit the Close Storyboard x again and set the values in Transform/Translate back to 0 Wiring Up the Animations Okay, now go back to Visual Studio.  Youll get a prompt due to the modification of MainPage.xaml.  Hit Yes. In the designer, click on the welcome Border element.  In the Property Browser, hit the Events button, then double click each of ManipulationStarted, ManipulationDelta, ManipulationCompleted.  Youll need to flip back to the designer from code, after each double click. Its code time.  Here we go. Here, three event handlers have been created for us: welcome_ManipulationStarted: This will execute when a manipulation begins.  Think of it as MouseDown. welcome_ManipulationDelta: This executes each time a manipulation changes.  Think MouseMove. welcome_ManipulationCompleted: This will  execute when the manipulation ends. Think MouseUp. Now, in ManipuliationStarted, we want to kick off the throb animation that we called touchAnimation.  Thats easy: 1: private void welcome_ManipulationStarted(object sender, ManipulationStartedEventArgs e) 2: { 3: touchStoryboard.Begin(); 4: } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Likewise, when the manipulation completes, we want to re-center the welcome visual with our bounce animation: 1: private void welcome_ManipulationCompleted(object sender, ManipulationCompletedEventArgs e) 2: { 3: releaseStoryboard.Begin(); 4: } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Note there is actually a way to kick off these animations from Blend directly via something called Triggers, but I think its clearer to show whats going on like this.  A Trigger basically allows you to say When this event fires, trigger this Storyboard, so its the exact same logical process as above, but without the code. But how do we get the object to move?  Well, for that we really dont want an animation because we want it to respond immediately to user input. We do this by directly modifying the transform to match the offset for the manipulation, and then well let the animation bring it back to zero when the manipulation completes.  The manipulation events do a great job of keeping track of all the stuff that you usually had to do yourself when doing drags: where you started from, how far youve moved, etc. So we can easily modify the position as below: 1: private void welcome_ManipulationDelta(object sender, ManipulationDeltaEventArgs e) 2: { 3: CompositeTransform transform = (CompositeTransform)welcome.RenderTransform; 4:   5: transform.TranslateX = e.CumulativeManipulation.Translation.X; 6: transform.TranslateY = e.CumulativeManipulation.Translation.Y; 7: } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Thats it! Go ahead and run the app in the emulator.  I suggest running without the debugger, its a little faster (CTRL+F5).  If youve got a machine that supports DirectX 10, youll see nice smooth GPU accelerated graphics, which also what it looks like on the phone, running at about 60 frames per second.  If your machine does not support DX10 (like the laptop Im writing this on!), it wont be quite a smooth so youll have to take my word for it! Comparing Against the iPhone This is an example where the flexibility and power of XAML meets the tooling of Visual Studio and Blend, and the whole experience really shines.  So, for several things that are declarative and 100% toolable with the Windows Phone 7 Series, this example does them with code on the iPhone.  In parens is the lines of code that I count to do these operations. PlacardView.m: 19 total LOC Creating the view that hosts the button-like image and the text Drawing the image that is the background of the button Drawing the Welcome text over the image (I think you could technically do this step and/or the prior one using Interface Builder) MoveMeView.m:  63 total LOC Constructing and running the scale (throb) animation (25) Constructing the path describing the animation back to center plus bounce effect (38) Beyond the code count, yy experience with doing this kind of thing in code is that its VERY time intensive.  When I was a developer back on Windows Forms, doing GDI+ drawing, we did this stuff a lot, and it took forever!  You write some code and even once you get it basically working, you see its not quite right, you go back, tweak the interval, or the math a bit, run it again, etc.  You can take a look at the iPhone code here to judge for yourself.  Scroll down to animatePlacardViewToCenter toward the bottom.  I dont think this code is terribly complicated, but its not what Id call simple and its not at all simple to get right. And then theres a few other lines of code running around for setting up the ViewController and the Views, about 15 lines between MoveMeAppDelegate, PlacardView, and MoveMeView, plus the assorted decls in the h files. Adding those up, I conservatively get something like 100 lines of code (19+63+15+decls) on iPhone that I have to write, by hand, to make this project work. The lines of code that I wrote in the examples above is 5 lines of code on Windows Phone 7 Series. In terms of incremental concept counts beyond the HelloWorld app, heres a shot at that: iPhone: Drawing Images Drawing Text Handling touch events Creating animations Scaling animations Building a path and animating along that Windows Phone 7 Series: Laying out UI in Blend Creating & testing basic animations in Blend Handling touch events Invoking animations from code This was actually the first example I tried converting, even before I did the HelloWorld, and I was pretty surprised.  Some of this is luck that this app happens to match up with the Windows Phone 7 Series platform just perfectly.  In terms of time, I wrote the above application, from scratch, in about 10 minutes.  I dont know how long it would take a very skilled iPhone developer to write MoveMe on that iPhone from scratch, but if I was to write it on Silverlight in the same way (e.g. all via code), I think it would likely take me at least an hour or two to get it all working right, maybe more if I ended up picking the wrong strategy or couldnt get the math right, etc. Making Some Tweaks Silverlight contains a feature called Projections to do a variety of 3D-like effects with a 2D surface. So lets play with that a bit. Go back to Blend and select the welcome Border in the object tree.  In its properties, scroll down to the bottom, open Transform, and see Projection at the bottom.  Set X,Y,Z to 90.  Youll see the element kind of disappear, replaced by a thin blue line. Now Create a new animation called startupStoryboard. Set its key time to .5 seconds in the timeline view Set the projection values above to 0 for X, Y, and Z. Save Go back to Visual Studio, and in the constructor, add the following bold code (lines 7-9 to the constructor: 1: public MainPage() 2: { 3: InitializeComponent(); 4:   5: SupportedOrientations = SupportedPageOrientation.Portrait; 6:   7: this.Loaded += (s, e) => 8: { 9: startupStoryboard.Begin(); 10: }; 11: } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } If the code above looks funny, its using something called a lambda in C#, which is an inline anonymous method.  Its just a handy shorthand for creating a handler like the manipulation ones above. So with this youll get a nice 3D looking fly in effect when the app starts up.  Here it is, in flight: Pretty cool!Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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• High Load mysql on Debian server stops every day. Why?

  - by Oleg Abrazhaev

  I have Debian server with 32 gb memory. And there is apache2, memcached and nginx on this server. Memory load always on maximum. Only 500m free. Most memory leak do MySql. Apache only 70 clients configured, other services small memory usage. When mysql use all memory it stops. And nothing works, need mysql reboot. Mysql configured use maximum 24 gb memory. I have hight weight InnoDB bases. (400000 rows, 30 gb). And on server multithread daemon, that makes many inserts in this tables, thats why InnoDB. There is my mysql config. [mysqld] # # * Basic Settings # default-time-zone = "+04:00" user = mysql pid-file = /var/run/mysqld/mysqld.pid socket = /var/run/mysqld/mysqld.sock port = 3306 basedir = /usr datadir = /var/lib/mysql tmpdir = /tmp language = /usr/share/mysql/english skip-external-locking default-time-zone='Europe/Moscow' # # Instead of skip-networking the default is now to listen only on # localhost which is more compatible and is not less secure. # # * Fine Tuning # #low_priority_updates = 1 concurrent_insert = ALWAYS wait_timeout = 600 interactive_timeout = 600 #normal key_buffer_size = 2024M #key_buffer_size = 1512M #70% hot cache key_cache_division_limit= 70 #16-32 max_allowed_packet = 32M #1-16M thread_stack = 8M #40-50 thread_cache_size = 50 #orderby groupby sort sort_buffer_size = 64M #same myisam_sort_buffer_size = 400M #temp table creates when group_by tmp_table_size = 3000M #tables in memory max_heap_table_size = 3000M #on disk open_files_limit = 10000 table_cache = 10000 join_buffer_size = 5M # This replaces the startup script and checks MyISAM tables if needed # the first time they are touched myisam-recover = BACKUP #myisam_use_mmap = 1 max_connections = 200 thread_concurrency = 8 # # * Query Cache Configuration # #more ignored query_cache_limit = 50M query_cache_size = 210M #on query cache query_cache_type = 1 # # * Logging and Replication # # Both location gets rotated by the cronjob. # Be aware that this log type is a performance killer. #log = /var/log/mysql/mysql.log # # Error logging goes to syslog. This is a Debian improvement :) # # Here you can see queries with especially long duration log_slow_queries = /var/log/mysql/mysql-slow.log long_query_time = 1 log-queries-not-using-indexes # # The following can be used as easy to replay backup logs or for replication. # note: if you are setting up a replication slave, see README.Debian about # other settings you may need to change. #server-id = 1 #log_bin = /var/log/mysql/mysql-bin.log server-id = 1 log-bin = /var/lib/mysql/mysql-bin #replicate-do-db = gate log-bin-index = /var/lib/mysql/mysql-bin.index log-error = /var/lib/mysql/mysql-bin.err relay-log = /var/lib/mysql/relay-bin relay-log-info-file = /var/lib/mysql/relay-bin.info relay-log-index = /var/lib/mysql/relay-bin.index binlog_do_db = 24avia expire_logs_days = 10 max_binlog_size = 100M read_buffer_size = 4024288 innodb_buffer_pool_size = 5000M innodb_flush_log_at_trx_commit = 2 innodb_thread_concurrency = 8 table_definition_cache = 2000 group_concat_max_len = 16M #binlog_do_db = gate #binlog_ignore_db = include_database_name # # * BerkeleyDB # # Using BerkeleyDB is now discouraged as its support will cease in 5.1.12. #skip-bdb # # * InnoDB # # InnoDB is enabled by default with a 10MB datafile in /var/lib/mysql/. # Read the manual for more InnoDB related options. There are many! # You might want to disable InnoDB to shrink the mysqld process by circa 100MB. #skip-innodb # # * Security Features # # Read the manual, too, if you want chroot! # chroot = /var/lib/mysql/ # # For generating SSL certificates I recommend the OpenSSL GUI "tinyca". # # ssl-ca=/etc/mysql/cacert.pem # ssl-cert=/etc/mysql/server-cert.pem # ssl-key=/etc/mysql/server-key.pem [mysqldump] quick quote-names max_allowed_packet = 500M [mysql] #no-auto-rehash # faster start of mysql but no tab completition [isamchk] key_buffer = 32M key_buffer_size = 512M # # * NDB Cluster # # See /usr/share/doc/mysql-server-*/README.Debian for more information. # # The following configuration is read by the NDB Data Nodes (ndbd processes) # not from the NDB Management Nodes (ndb_mgmd processes). # # [MYSQL_CLUSTER] # ndb-connectstring=127.0.0.1 # # * IMPORTANT: Additional settings that can override those from this file! # The files must end with '.cnf', otherwise they'll be ignored. # !includedir /etc/mysql/conf.d/ Please, help me make it stable. Memory used /etc/mysql # free total used free shared buffers cached Mem: 32930800 32766424 164376 0 139208 23829196 -/+ buffers/cache: 8798020 24132780 Swap: 33553328 44660 33508668 Maybe my problem not in memory, but MySQL stops every day. As you can see, cache memory free 24 gb. Thank to Michael Hampton? for correction. Load overage on server 3.5. Maybe hdd or another problem? Maybe my config not optimal for 30gb InnoDB ? I'm already try mysqltuner and tunung-primer.sh , but they marked all green. Mysqltuner output mysqltuner >> MySQLTuner 1.0.1 - Major Hayden <[email protected]> >> Bug reports, feature requests, and downloads at http://mysqltuner.com/ >> Run with '--help' for additional options and output filtering -------- General Statistics -------------------------------------------------- [--] Skipped version check for MySQLTuner script [OK] Currently running supported MySQL version 5.5.24-9-log [OK] Operating on 64-bit architecture -------- Storage Engine Statistics ------------------------------------------- [--] Status: -Archive -BDB -Federated +InnoDB -ISAM -NDBCluster [--] Data in MyISAM tables: 112G (Tables: 1528) [--] Data in InnoDB tables: 39G (Tables: 340) [--] Data in PERFORMANCE_SCHEMA tables: 0B (Tables: 17) [!!] Total fragmented tables: 344 -------- Performance Metrics ------------------------------------------------- [--] Up for: 8h 18m 33s (14M q [478.333 qps], 259K conn, TX: 9B, RX: 5B) [--] Reads / Writes: 84% / 16% [--] Total buffers: 10.5G global + 81.1M per thread (200 max threads) [OK] Maximum possible memory usage: 26.3G (83% of installed RAM) [OK] Slow queries: 1% (259K/14M) [!!] Highest connection usage: 100% (201/200) [OK] Key buffer size / total MyISAM indexes: 1.5G/5.6G [OK] Key buffer hit rate: 100.0% (6B cached / 1M reads) [OK] Query cache efficiency: 74.3% (8M cached / 11M selects) [OK] Query cache prunes per day: 0 [OK] Sorts requiring temporary tables: 0% (0 temp sorts / 247K sorts) [!!] Joins performed without indexes: 106025 [!!] Temporary tables created on disk: 49% (351K on disk / 715K total) [OK] Thread cache hit rate: 99% (249 created / 259K connections) [!!] Table cache hit rate: 15% (2K open / 13K opened) [OK] Open file limit used: 15% (3K/20K) [OK] Table locks acquired immediately: 99% (4M immediate / 4M locks) [!!] InnoDB data size / buffer pool: 39.4G/5.9G -------- Recommendations ----------------------------------------------------- General recommendations: Run OPTIMIZE TABLE to defragment tables for better performance MySQL started within last 24 hours - recommendations may be inaccurate Reduce or eliminate persistent connections to reduce connection usage Adjust your join queries to always utilize indexes Temporary table size is already large - reduce result set size Reduce your SELECT DISTINCT queries without LIMIT clauses Increase table_cache gradually to avoid file descriptor limits Variables to adjust: max_connections (> 200) wait_timeout (< 600) interactive_timeout (< 600) join_buffer_size (> 5.0M, or always use indexes with joins) table_cache (> 10000) innodb_buffer_pool_size (>= 39G) Mysql primer output -- MYSQL PERFORMANCE TUNING PRIMER -- - By: Matthew Montgomery - MySQL Version 5.5.24-9-log x86_64 Uptime = 0 days 8 hrs 20 min 50 sec Avg. qps = 478 Total Questions = 14369568 Threads Connected = 16 Warning: Server has not been running for at least 48hrs. It may not be safe to use these recommendations To find out more information on how each of these runtime variables effects performance visit: http://dev.mysql.com/doc/refman/5.5/en/server-system-variables.html Visit http://www.mysql.com/products/enterprise/advisors.html for info about MySQL's Enterprise Monitoring and Advisory Service SLOW QUERIES The slow query log is enabled. Current long_query_time = 1.000000 sec. You have 260626 out of 14369701 that take longer than 1.000000 sec. to complete Your long_query_time seems to be fine BINARY UPDATE LOG The binary update log is enabled Binlog sync is not enabled, you could loose binlog records during a server crash WORKER THREADS Current thread_cache_size = 50 Current threads_cached = 45 Current threads_per_sec = 0 Historic threads_per_sec = 0 Your thread_cache_size is fine MAX CONNECTIONS Current max_connections = 200 Current threads_connected = 11 Historic max_used_connections = 201 The number of used connections is 100% of the configured maximum. You should raise max_connections INNODB STATUS Current InnoDB index space = 214 M Current InnoDB data space = 39.40 G Current InnoDB buffer pool free = 0 % Current innodb_buffer_pool_size = 5.85 G Depending on how much space your innodb indexes take up it may be safe to increase this value to up to 2 / 3 of total system memory MEMORY USAGE Max Memory Ever Allocated : 23.46 G Configured Max Per-thread Buffers : 15.84 G Configured Max Global Buffers : 7.54 G Configured Max Memory Limit : 23.39 G Physical Memory : 31.40 G Max memory limit seem to be within acceptable norms KEY BUFFER Current MyISAM index space = 5.61 G Current key_buffer_size = 1.47 G Key cache miss rate is 1 : 5578 Key buffer free ratio = 77 % Your key_buffer_size seems to be fine QUERY CACHE Query cache is enabled Current query_cache_size = 200 M Current query_cache_used = 101 M Current query_cache_limit = 50 M Current Query cache Memory fill ratio = 50.59 % Current query_cache_min_res_unit = 4 K MySQL won't cache query results that are larger than query_cache_limit in size SORT OPERATIONS Current sort_buffer_size = 64 M Current read_rnd_buffer_size = 256 K Sort buffer seems to be fine JOINS Current join_buffer_size = 5.00 M You have had 106606 queries where a join could not use an index properly You have had 8 joins without keys that check for key usage after each row join_buffer_size >= 4 M This is not advised You should enable "log-queries-not-using-indexes" Then look for non indexed joins in the slow query log. OPEN FILES LIMIT Current open_files_limit = 20210 files The open_files_limit should typically be set to at least 2x-3x that of table_cache if you have heavy MyISAM usage. Your open_files_limit value seems to be fine TABLE CACHE Current table_open_cache = 10000 tables Current table_definition_cache = 2000 tables You have a total of 1910 tables You have 2151 open tables. The table_cache value seems to be fine TEMP TABLES Current max_heap_table_size = 2.92 G Current tmp_table_size = 2.92 G Of 366426 temp tables, 49% were created on disk Perhaps you should increase your tmp_table_size and/or max_heap_table_size to reduce the number of disk-based temporary tables Note! BLOB and TEXT columns are not allow in memory tables. If you are using these columns raising these values might not impact your ratio of on disk temp tables. TABLE SCANS Current read_buffer_size = 3 M Current table scan ratio = 2846 : 1 read_buffer_size seems to be fine TABLE LOCKING Current Lock Wait ratio = 1 : 185 You may benefit from selective use of InnoDB. If you have long running SELECT's against MyISAM tables and perform frequent updates consider setting 'low_priority_updates=1'

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• Class Mapping Error: 'T' must be a non-abstract type with a public parameterless constructor

  - by Amit Ranjan

  Hi, While mapping class i am getting error 'T' must be a non-abstract type with a public parameterless constructor in order to use it as parameter 'T' in the generic type or method. Below is my SqlReaderBase Class public abstract class SqlReaderBase<T> : ConnectionProvider { #region Abstract Methods protected abstract string commandText { get; } protected abstract CommandType commandType { get; } protected abstract Collection<IDataParameter> GetParameters(IDbCommand command); **protected abstract MapperBase<T> GetMapper();** #endregion #region Non Abstract Methods /// <summary> /// Method to Execute Select Queries for Retrieveing List of Result /// </summary> /// <returns></returns> public Collection<T> ExecuteReader() { //Collection of Type on which Template is applied Collection<T> collection = new Collection<T>(); // initializing connection using (IDbConnection connection = GetConnection()) { try { // creates command for sql operations IDbCommand command = connection.CreateCommand(); // assign connection to command command.Connection = connection; // assign query command.CommandText = commandText; //state what type of query is used, text, table or Sp command.CommandType = commandType; // retrieves parameter from IDataParameter Collection and assigns it to command object foreach (IDataParameter param in GetParameters(command)) command.Parameters.Add(param); // Establishes connection with database server connection.Open(); // Since it is designed for executing Select statements that will return a list of results // so we will call command's execute reader method that return a Forward Only reader with // list of results inside. using (IDataReader reader = command.ExecuteReader()) { try { // Call to Mapper Class of the template to map the data to its // respective fields MapperBase<T> mapper = GetMapper(); collection = mapper.MapAll(reader); } catch (Exception ex) // catch exception { throw ex; // log errr } finally { reader.Close(); reader.Dispose(); } } } catch (Exception ex) { throw ex; } finally { connection.Close(); connection.Dispose(); } } return collection; } #endregion } What I am trying to do is , I am executine some command and filling my class dynamically. The class is given below: namespace FooZo.Core { public class Restaurant { #region Private Member Variables private int _restaurantId = 0; private string _email = string.Empty; private string _website = string.Empty; private string _name = string.Empty; private string _address = string.Empty; private string _phone = string.Empty; private bool _hasMenu = false; private string _menuImagePath = string.Empty; private int _cuisine = 0; private bool _hasBar = false; private bool _hasHomeDelivery = false; private bool _hasDineIn = false; private int _type = 0; private string _restaurantImagePath = string.Empty; private string _serviceAvailableTill = string.Empty; private string _serviceAvailableFrom = string.Empty; public string Name { get { return _name; } set { _name = value; } } public string Address { get { return _address; } set { _address = value; } } public int RestaurantId { get { return _restaurantId; } set { _restaurantId = value; } } public string Website { get { return _website; } set { _website = value; } } public string Email { get { return _email; } set { _email = value; } } public string Phone { get { return _phone; } set { _phone = value; } } public bool HasMenu { get { return _hasMenu; } set { _hasMenu = value; } } public string MenuImagePath { get { return _menuImagePath; } set { _menuImagePath = value; } } public string RestaurantImagePath { get { return _restaurantImagePath; } set { _restaurantImagePath = value; } } public int Type { get { return _type; } set { _type = value; } } public int Cuisine { get { return _cuisine; } set { _cuisine = value; } } public bool HasBar { get { return _hasBar; } set { _hasBar = value; } } public bool HasHomeDelivery { get { return _hasHomeDelivery; } set { _hasHomeDelivery = value; } } public bool HasDineIn { get { return _hasDineIn; } set { _hasDineIn = value; } } public string ServiceAvailableFrom { get { return _serviceAvailableFrom; } set { _serviceAvailableFrom = value; } } public string ServiceAvailableTill { get { return _serviceAvailableTill; } set { _serviceAvailableTill = value; } } #endregion public Restaurant() { } } } For filling my class properties dynamically i have another class called MapperBase Class with following methods: public abstract class MapperBase<T> where T : new() { protected T Map(IDataRecord record) { T instance = new T(); string fieldName; PropertyInfo[] properties = typeof(T).GetProperties(); for (int i = 0; i < record.FieldCount; i++) { fieldName = record.GetName(i); foreach (PropertyInfo property in properties) { if (property.Name == fieldName) { property.SetValue(instance, record[i], null); } } } return instance; } public Collection<T> MapAll(IDataReader reader) { Collection<T> collection = new Collection<T>(); while (reader.Read()) { collection.Add(Map(reader)); } return collection; } } There is another class which inherits the SqlreaderBaseClass called DefaultSearch. Code is below public class DefaultSearch: SqlReaderBase<Restaurant> { protected override string commandText { get { return "Select Name from vw_Restaurants"; } } protected override CommandType commandType { get { return CommandType.Text; } } protected override Collection<IDataParameter> GetParameters(IDbCommand command) { Collection<IDataParameter> parameters = new Collection<IDataParameter>(); parameters.Clear(); return parameters; } protected override MapperBase<Restaurant> GetMapper() { MapperBase<Restaurant> mapper = new RMapper(); return mapper; } } But whenever I tried to build , I am getting error 'T' must be a non-abstract type with a public parameterless constructor in order to use it as parameter 'T' in the generic type or method. Even T here is Restaurant has a Parameterless Public constructor.

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• Why is my WCF Rest Service on IIS7 Authenticating TWICE!?!?

  - by TheAggie

  Ok, if someone could shed some light on this for me, I would greatly appreciate it. So here we go. I had a rest service running fine the other day but after I accidentally overwrote the web.config all hell broke loose. I've spent the past day and a half trying to sort things out but I can't seem to figure out what is missing or misplaced. So, I've designed this service around WCF Rest Contrib (http://wcfrestcontrib.codeplex.com)'s authentication process. Now, I can get this working fine on my localhost w/ the current web.config (minus the endpoint entry) but once I upload it to discountasp and select "basic authorization" in the ISS7 Manager, it appears that I'm getting authenticated twice! Once using my discount asp.net user/pass and then the next time using the application user/pass. Unfortunately I only provide one set of credentials and don't want to hard code my discountasp account info into the app. Like I said before, this worked fine a few days ago. Anyway. here is my web.config as it is now: <?xml version="1.0"?> <configuration> <connectionStrings> <add name="SQL2008_ConnectionString" connectionString="Data Source=sql2k8xx.discountasp.net;Initial Catalog=SQL2008_xx;Persist Security Info=True;User ID=SQL2008_xx_user;Password=myPass" providerName="System.Data.SqlClient" /> </connectionStrings> <system.web> <httpRuntime maxRequestLength="204800" executionTimeout="3600"/> <compilation debug="true"> <assemblies> <add assembly="System.Core, Version=3.5.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089"/> <add assembly="System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/> </assemblies> </compilation> <httpModules> <add name="ServiceAnonymityModule" type="WcfRestContrib.Web.ServiceAnonymityModule, WcfRestContrib"/> </httpModules> </system.web> <system.codedom> <compilers> <compiler language="c#;cs;csharp" extension=".cs" warningLevel="4" type="Microsoft.CSharp.CSharpCodeProvider, System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"> <providerOption name="CompilerVersion" value="v3.5"/> <providerOption name="WarnAsError" value="false"/> </compiler> </compilers> </system.codedom> <system.webServer> <validation validateIntegratedModeConfiguration="false"/> <modules> <remove name="ServiceAnonymityModule"/> <add name="ServiceAnonymityModule" type="WcfRestContrib.Web.ServiceAnonymityModule, WcfRestContrib"/> </modules> <handlers> <remove name="WebServiceHandlerFactory-Integrated"/> </handlers> </system.webServer> <system.diagnostics> <trace autoflush="true" /> </system.diagnostics> <system.serviceModel> <serviceHostingEnvironment aspNetCompatibilityEnabled="false"> <baseAddressPrefixFilters> <add prefix="http://www.mydomain.com/myServiceBaseAddress"/> </baseAddressPrefixFilters> </serviceHostingEnvironment> <extensions> <behaviorExtensions> <add name="webAuthentication" type="WcfRestContrib.ServiceModel.Configuration.WebAuthentication.ConfigurationBehaviorElement, WcfRestContrib, Version=1.0.5.0, Culture=neutral, PublicKeyToken=89183999a8dc93b5"/> <add name="errorHandler" type="WcfRestContrib.ServiceModel.Configuration.ErrorHandler.BehaviorElement, WcfRestContrib, Version=1.0.5.0, Culture=neutral, PublicKeyToken=89183999a8dc93b5"/> <add name="webFormatter" type="WcfRestContrib.ServiceModel.Configuration.WebDispatchFormatter.ConfigurationBehaviorElement, WcfRestContrib, Version=1.0.5.0, Culture=neutral, PublicKeyToken=89183999a8dc93b5"/> <add name="webErrorHandler" type="WcfRestContrib.ServiceModel.Configuration.WebErrorHandler.ConfigurationBehaviorElement, WcfRestContrib, Version=1.0.5.0, Culture=neutral, PublicKeyToken=89183999a8dc93b5"/> </behaviorExtensions> </extensions> <bindings> <customBinding> <binding name="HttpStreamedRest"> <httpTransport maxReceivedMessageSize="209715200" manualAddressing="true" /> </binding> <binding name="HttpsStreamedRest"> <httpsTransport maxReceivedMessageSize="209715200" manualAddressing="true" /> </binding> </customBinding> </bindings> <behaviors> <serviceBehaviors> <behavior name="Rest"> <webAuthentication requireSecureTransport="false" authenticationHandlerType="WcfRestContrib.ServiceModel.Dispatcher.WebBasicAuthenticationHandler, WcfRestContrib" usernamePasswordValidatorType="MyLibrary.Runtime.SecurityValidator, MyLibrary" source="MyRESTServiceRealm"/> <webFormatter> <formatters defaultMimeType="application/xml"> <formatter mimeTypes="application/xml,text/xml" type="WcfRestContrib.ServiceModel.Dispatcher.Formatters.PoxDataContract, WcfRestContrib"/> <formatter mimeTypes="application/json" type="WcfRestContrib.ServiceModel.Dispatcher.Formatters.DataContractJson, WcfRestContrib"/> <formatter mimeTypes="application/x-www-form-urlencoded" type="WcfRestContrib.ServiceModel.Dispatcher.Formatters.FormUrlEncoded, WcfRestContrib"/> </formatters> </webFormatter> <errorHandler errorHandlerType="WcfRestContrib.ServiceModel.Web.WebErrorHandler, WcfRestContrib"/> <webErrorHandler returnRawException="true" logHandlerType="MyLibrary.Runtime.LogHandler, MyLibrary" unhandledErrorMessage="An error has occured processing your request. Please contact technical support for further assistance."/> </behavior> </serviceBehaviors> </behaviors> </system.serviceModel> </configuration> So, whenever I upload this and change the ISS setting to Basic Authentication, it looks like it is trying to use the default handler for authentication as if I try to enter my web app user/pass, I get an error screen which has the following detailed information about the moduel/handler Detailed Error Information Module: IIS Web Core Notification: AuthenticateRequest Handler: svc-ISAPI-2.0 Error Code: 0x80070005 Requested URL: http://www.mydomain.com:80/MyService.../MyService.svc Physical Path: E:\web\xxxxxx\htdocs\MyServiceBaseAddress\MyService.svc Logon Method: Not yet determined Logon User: Not yet determined Now for the fun stuff... i tried providing my discountasp.net account username/password for kicks and sure enough it responded properly for any [OperationContract] which doesn't have [OperationAuthentication] defined (which is only one or two of the operations I have). I thought this was strange, so I looked at fiddler and saw something interesting. Whenever I try request a procedure with [OperationAuthentication] defined and provide my discountasp.net username/pass I get two different "WWW-Authenticate" headers back in Fiddler: WWW-Authenticate: Basic realm="MyRESTServiceRealm" WWW-Authenticate: Basic realm="www.mydomain.com" On the other hand, if I try to access the same procedures with only my application's user/pass, I only get the site's header: WWW-Authenticate: Basic realm="www.mydomain.com" My hypothesis is that for some reason I'm having to pass through the default "Basic Authorization" layer set by IIS before I can get to the application's "Custom Basic Authorization" layer. After verifying this by created an identical user/pass for my service that I use for my discountasp.net account, I was able to successfully pass both layers of authentication without any issues... so I think I can conclude that this is indeed the issue. Now how do I disable the default one? Do I need to do this in the IIS Manager, or in the web.config? Anyway, I have absolutely no idea how this is possible or what I need to do to resolve the issue, but I know that something is seriously out of whack. Any suggestions would be greatly appreciated! Thanks.

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• Solving embarassingly parallel problems using Python multiprocessing

  - by gotgenes

  How does one use multiprocessing to tackle embarrassingly parallel problems? Embarassingly parallel problems typically consist of three basic parts: Read input data (from a file, database, tcp connection, etc.). Run calculations on the input data, where each calculation is independent of any other calculation. Write results of calculations (to a file, database, tcp connection, etc.). We can parallelize the program in two dimensions: Part 2 can run on multiple cores, since each calculation is independent; order of processing doesn't matter. Each part can run independently. Part 1 can place data on an input queue, part 2 can pull data off the input queue and put results onto an output queue, and part 3 can pull results off the output queue and write them out. This seems a most basic pattern in concurrent programming, but I am still lost in trying to solve it, so let's write a canonical example to illustrate how this is done using multiprocessing. Here is the example problem: Given a CSV file with rows of integers as input, compute their sums. Separate the problem into three parts, which can all run in parallel: Process the input file into raw data (lists/iterables of integers) Calculate the sums of the data, in parallel Output the sums Below is traditional, single-process bound Python program which solves these three tasks: #!/usr/bin/env python # -*- coding: UTF-8 -*- # basicsums.py """A program that reads integer values from a CSV file and writes out their sums to another CSV file. """ import csv import optparse import sys def make_cli_parser(): """Make the command line interface parser.""" usage = "\n\n".join(["python %prog INPUT_CSV OUTPUT_CSV", __doc__, """ ARGUMENTS: INPUT_CSV: an input CSV file with rows of numbers OUTPUT_CSV: an output file that will contain the sums\ """]) cli_parser = optparse.OptionParser(usage) return cli_parser def parse_input_csv(csvfile): """Parses the input CSV and yields tuples with the index of the row as the first element, and the integers of the row as the second element. The index is zero-index based. :Parameters: - `csvfile`: a `csv.reader` instance """ for i, row in enumerate(csvfile): row = [int(entry) for entry in row] yield i, row def sum_rows(rows): """Yields a tuple with the index of each input list of integers as the first element, and the sum of the list of integers as the second element. The index is zero-index based. :Parameters: - `rows`: an iterable of tuples, with the index of the original row as the first element, and a list of integers as the second element """ for i, row in rows: yield i, sum(row) def write_results(csvfile, results): """Writes a series of results to an outfile, where the first column is the index of the original row of data, and the second column is the result of the calculation. The index is zero-index based. :Parameters: - `csvfile`: a `csv.writer` instance to which to write results - `results`: an iterable of tuples, with the index (zero-based) of the original row as the first element, and the calculated result from that row as the second element """ for result_row in results: csvfile.writerow(result_row) def main(argv): cli_parser = make_cli_parser() opts, args = cli_parser.parse_args(argv) if len(args) != 2: cli_parser.error("Please provide an input file and output file.") infile = open(args[0]) in_csvfile = csv.reader(infile) outfile = open(args[1], 'w') out_csvfile = csv.writer(outfile) # gets an iterable of rows that's not yet evaluated input_rows = parse_input_csv(in_csvfile) # sends the rows iterable to sum_rows() for results iterable, but # still not evaluated result_rows = sum_rows(input_rows) # finally evaluation takes place as a chain in write_results() write_results(out_csvfile, result_rows) infile.close() outfile.close() if __name__ == '__main__': main(sys.argv[1:]) Let's take this program and rewrite it to use multiprocessing to parallelize the three parts outlined above. Below is a skeleton of this new, parallelized program, that needs to be fleshed out to address the parts in the comments: #!/usr/bin/env python # -*- coding: UTF-8 -*- # multiproc_sums.py """A program that reads integer values from a CSV file and writes out their sums to another CSV file, using multiple processes if desired. """ import csv import multiprocessing import optparse import sys NUM_PROCS = multiprocessing.cpu_count() def make_cli_parser(): """Make the command line interface parser.""" usage = "\n\n".join(["python %prog INPUT_CSV OUTPUT_CSV", __doc__, """ ARGUMENTS: INPUT_CSV: an input CSV file with rows of numbers OUTPUT_CSV: an output file that will contain the sums\ """]) cli_parser = optparse.OptionParser(usage) cli_parser.add_option('-n', '--numprocs', type='int', default=NUM_PROCS, help="Number of processes to launch [DEFAULT: %default]") return cli_parser def main(argv): cli_parser = make_cli_parser() opts, args = cli_parser.parse_args(argv) if len(args) != 2: cli_parser.error("Please provide an input file and output file.") infile = open(args[0]) in_csvfile = csv.reader(infile) outfile = open(args[1], 'w') out_csvfile = csv.writer(outfile) # Parse the input file and add the parsed data to a queue for # processing, possibly chunking to decrease communication between # processes. # Process the parsed data as soon as any (chunks) appear on the # queue, using as many processes as allotted by the user # (opts.numprocs); place results on a queue for output. # # Terminate processes when the parser stops putting data in the # input queue. # Write the results to disk as soon as they appear on the output # queue. # Ensure all child processes have terminated. # Clean up files. infile.close() outfile.close() if __name__ == '__main__': main(sys.argv[1:]) These pieces of code, as well as another piece of code that can generate example CSV files for testing purposes, can be found on github. I would appreciate any insight here as to how you concurrency gurus would approach this problem. Here are some questions I had when thinking about this problem. Bonus points for addressing any/all: Should I have child processes for reading in the data and placing it into the queue, or can the main process do this without blocking until all input is read? Likewise, should I have a child process for writing the results out from the processed queue, or can the main process do this without having to wait for all the results? Should I use a processes pool for the sum operations? If yes, what method do I call on the pool to get it to start processing the results coming into the input queue, without blocking the input and output processes, too? apply_async()? map_async()? imap()? imap_unordered()? Suppose we didn't need to siphon off the input and output queues as data entered them, but could wait until all input was parsed and all results were calculated (e.g., because we know all the input and output will fit in system memory). Should we change the algorithm in any way (e.g., not run any processes concurrently with I/O)?

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• XSLT 1.0 recursion

  - by DashaLuna

  I'm stuck with recursion, was wondering if anyone can help me out with it. I have <Receipts> and <Deposits> elements, that are not verbose, i.e. that a <Receipts> element doesn't have an attribute to show what <Deposit> it is towards. I need to figure out <Deposits> "still amount due" and when a last receipt towards it was paid if any. I'm trying to do it with the following code: The idea was to take 1st deposit and see if there are receipts. If the deposit isn't fully paid and there are more receipts - call that recorsive function with all the same params except now count in following receipt. If there aren't any more receipts or deposit is payed - process it correctly (add required attributes). Otherwise proceed with 2nd deposit. And so on. However, the XSLT crashes with error message that "a processor stack has overflowed - possible cause is infinite template recursion" I would really appreciate any help/teps... I'm not that great with recursion and can't understand why mine here doesn't work. Thanks! :) <!-- Accumulate all the deposits with @DueAmount attribute --> <xsl:variable name="depositsClassified"> <xsl:call-template name="classifyDeposits"> <!-- a node-list of all Deposits elements ordered by DueDate Acs --> <xsl:with-param name="depositsAll" select="$deposits"/> <xsl:with-param name="depositPrevAmount" select="'0'"/> <!-- a node-list of all Receipts elements ordered by ReceivedDate Acs --> <xsl:with-param name="receiptsAll" select="$receiptsAsc"/> <xsl:with-param name="receiptCount" select="'1'"/> </xsl:call-template> </xsl:variable> <xsl:template name="classifyDeposits"> <xsl:param name="depositsAll"/> <xsl:param name="depositPrevAmount" select="'0'"/> <xsl:param name="receiptsAll"/> <xsl:param name="receiptCount"/> <xsl:if test="$deposits"> <!-- Do required operations for the 1st deposit --> <xsl:variable name="depositFirst" select="$depositsAll[1]"/> <xsl:variable name="receiptSum"> <xsl:choose> <xsl:when test="$receiptsAll"> <xsl:value-of select="sum($receiptsAll[position() &lt;= $receiptCount]/@ActionAmount)"/> </xsl:when> <xsl:otherwise>0</xsl:otherwise> </xsl:choose> </xsl:variable> <xsl:variable name="diff" select="$depositPrevAmount + $depositFirst/@DepositTotalAmount - $receiptSum"/> <xsl:choose> <xsl:when test="$diff &gt; 0 and $receiptCount &lt; $receiptsQuantityOf"> <xsl:call-template name="classifyDeposits"> <xsl:with-param name="depositsAll" select="$depositsAll"/> <xsl:with-param name="depositPrevAmount" select="$depositPrevAmount"/> <xsl:with-param name="receiptsAll" select="$receiptsAll"/> <xsl:with-param name="receiptCount" select="$receiptCount + 1"/> </xsl:call-template> </xsl:when> <xsl:otherwise> <!-- Record changes to the deposit (@DueAmount and receipt ReceivedDate) --> <xsl:apply-templates select="$depositFirst" mode="defineDeposit"> <xsl:with-param name="diff" select="$diff"/> <xsl:with-param name="latestReceiptForDeposit" select="$receiptsAll[position() = $receiptCount]"/> </xsl:apply-templates> <!-- Recursive call to the next deposit --> <xsl:call-template name="classifyDeposits"> <xsl:with-param name="depositsAll" select="$depositsAll[position() &gt; 1]"/> <xsl:with-param name="depositPrevAmount" select="$depositPrevAmount + $depositFirst/@DepositTotalAmount"/> <xsl:with-param name="receiptsAll" select="$receiptsAll"/> <xsl:with-param name="receiptCount" select="'1'"/> </xsl:call-template> </xsl:otherwise> </xsl:choose> </xsl:if> </xsl:template> <!-- Determine deposit's status, due amount and payment received date if any --> <xsl:template match="Deposits" mode="defineDeposit"> <xsl:param name="diff"/> <xsl:param name="latestReceiptForDeposit"/> <xsl:choose> <xsl:when test="$diff &lt;= 0"> <xsl:apply-templates select="." mode="addAttrs"> <xsl:with-param name="status" select="'paid'"/> <xsl:with-param name="dueAmount" select="'0'"/> <xsl:with-param name="receipt" select="$latestReceiptForDeposit"/> </xsl:apply-templates> </xsl:when> <xsl:when test="$diff = ./@DepositTotalAmount"> <xsl:apply-templates select="." mode="addAttrs"> <xsl:with-param name="status" select="'due'"/> <xsl:with-param name="dueAmount" select="$diff"/> </xsl:apply-templates> </xsl:when> <xsl:when test="$diff &lt; ./@DepositTotalAmount"> <xsl:apply-templates select="." mode="addAttrs"> <xsl:with-param name="status" select="'outstanding'"/> <xsl:with-param name="dueAmount" select="$diff"/> <xsl:with-param name="receipt" select="$latestReceiptForDeposit"/> </xsl:apply-templates> </xsl:when> <xsl:otherwise/> </xsl:choose> </xsl:template> <xsl:template match="Deposits" mode="addAttrs"> <xsl:param name="status"/> <xsl:param name="dueAmount"/> <xsl:param name="receipt" select="''"/> <!-- Constract a new MultiDeposits element with required info --> <xsl:copy> <xsl:copy-of select="./@*"/> <xsl:attribute name="Status"><xsl:value-of select="$status"/></xsl:attribute> <xsl:attribute name="DueAmount"><xsl:value-of select="$dueAmount"/></xsl:attribute> <xsl:if test="$receipt"> <xsl:attribute name="latestReceiptDate"> <xsl:value-of select="$receipt/@ActionDate"/> </xsl:attribute> </xsl:if> <xsl:copy-of select="./*"/> </xsl:copy> </xsl:template>

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• Connection drop problem with Hibernate-mysql-c3p0

  - by user344788

  hi all, This is an issue which I have seen all across the web. I will bring it up again as till now I don't have a fix for the same. I am using hibernate 3. mysql 5 and latest c3p0 jar. I am getting a broken pipe exception. Following is my hibernate.cfg file. com.mysql.jdbc.Driver org.hibernate.dialect.MySQLDialect <property name="hibernate.show_sql">true</property> <property name="hibernate.use_sql_comments">true</property> <property name="hibernate.current_session_context_class">thread</property> <property name="connection.autoReconnect">true</property> <property name="connection.autoReconnectForPools">true</property> <property name="connection.is-connection-validation-required">true</property> <!--<property name="c3p0.min_size">5</property> <property name="c3p0.max_size">20</property> <property name="c3p0.timeout">1800</property> <property name="c3p0.max_statements">50</property> --><property name="hibernate.connection.provider_class">org.hibernate.connection.C3P0ConnectionProvider </property> <property name="hibernate.c3p0.acquireRetryAttempts">30</property> <property name="hibernate.c3p0.acquireIncrement">5</property> <property name="hibernate.c3p0.automaticTestTable">C3P0TestTable</property> <property name="hibernate.c3p0.idleConnectionTestPeriod">36000</property> <property name="hibernate.c3p0.initialPoolSize">20</property> <property name="hibernate.c3p0.maxPoolSize">100</property> <property name="hibernate.c3p0.maxIdleTime">1200</property> <property name="hibernate.c3p0.maxStatements">50</property> <property name="hibernate.c3p0.minPoolSize">10</property>--> My connection pooling is occurring fine. During the day it is fine , but once i keep it idle over the night ,next day I find it giving me broken connection error. public class HibernateUtil { private static Logger log = Logger.getLogger(HibernateUtil.class); //private static Log log = LogFactory.getLog(HibernateUtil.class); private static Configuration configuration; private static SessionFactory sessionFactory; static { // Create the initial SessionFactory from the default configuration files try { log.debug("Initializing Hibernate"); // Read hibernate.properties, if present configuration = new Configuration(); // Use annotations: configuration = new AnnotationConfiguration(); // Read hibernate.cfg.xml (has to be present) configuration.configure(); // Build and store (either in JNDI or static variable) rebuildSessionFactory(configuration); log.debug("Hibernate initialized, call HibernateUtil.getSessionFactory()"); } catch (Throwable ex) { // We have to catch Throwable, otherwise we will miss // NoClassDefFoundError and other subclasses of Error log.error("Building SessionFactory failed.", ex); throw new ExceptionInInitializerError(ex); } } /** * Returns the Hibernate configuration that was used to build the SessionFactory. * * @return Configuration */ public static Configuration getConfiguration() { return configuration; } /** * Returns the global SessionFactory either from a static variable or a JNDI lookup. * * @return SessionFactory */ public static SessionFactory getSessionFactory() { String sfName = configuration.getProperty(Environment.SESSION_FACTORY_NAME); System.out.println("Current s name is "+sfName); if ( sfName != null) { System.out.println("Looking up SessionFactory in JNDI"); log.debug("Looking up SessionFactory in JNDI"); try { System.out.println("Returning new sssion factory"); return (SessionFactory) new InitialContext().lookup(sfName); } catch (NamingException ex) { throw new RuntimeException(ex); } } else if (sessionFactory == null) { System.out.println("calling rebuild session factory now"); rebuildSessionFactory(); } return sessionFactory; } /** * Closes the current SessionFactory and releases all resources. * <p> * The only other method that can be called on HibernateUtil * after this one is rebuildSessionFactory(Configuration). */ public static void shutdown() { log.debug("Shutting down Hibernate"); // Close caches and connection pools getSessionFactory().close(); // Clear static variables sessionFactory = null; } /** * Rebuild the SessionFactory with the static Configuration. * <p> * Note that this method should only be used with static SessionFactory * management, not with JNDI or any other external registry. This method also closes * the old static variable SessionFactory before, if it is still open. */ public static void rebuildSessionFactory() { log.debug("Using current Configuration to rebuild SessionFactory"); rebuildSessionFactory(configuration); } /** * Rebuild the SessionFactory with the given Hibernate Configuration. * <p> * HibernateUtil does not configure() the given Configuration object, * it directly calls buildSessionFactory(). This method also closes * the old static variable SessionFactory before, if it is still open. * * @param cfg */ public static void rebuildSessionFactory(Configuration cfg) { log.debug("Rebuilding the SessionFactory from given Configuration"); if (sessionFactory != null && !sessionFactory.isClosed()) sessionFactory.close(); if (cfg.getProperty(Environment.SESSION_FACTORY_NAME) != null) { log.debug("Managing SessionFactory in JNDI"); cfg.buildSessionFactory(); } else { log.debug("Holding SessionFactory in static variable"); sessionFactory = cfg.buildSessionFactory(); } configuration = cfg; } } Above is my code for the session factory. And I have only select operations . And below is the method which is used most often to execute my select queries. One tricky thing which I am not understanding is in my findById method i am using this line of code getSession().beginTransaction(); without which it gives me an error saying that this cannot happpen without a transaction. But nowhere I am closing this transaction. And thers no method to close a transaction apart from commit or rollback (as far as i know) which are not applicable for select statements. public T findById(ID id, boolean lock) throws HibernateException, DAOException { log.debug("findNyId invoked with ID ="+id+"and lock ="+lock); T entity; getSession().beginTransaction(); if (lock) entity = (T) getSession().load(getPersistentClass(), id, LockMode.UPGRADE); else entity = (T) getSession().load(getPersistentClass(), id); return entity; } Can anyone please suggest what can I do ? I have tried out almost every solution available via googling, on stackoverlow or on hibernate forums with no avail. (And increasing wait_timeout on mysql is not a valid option in my case).

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• Scala parser combinator runs out of memory

  - by user3217013

  I wrote the following parser in Scala using the parser combinators: import scala.util.parsing.combinator._ import scala.collection.Map import scala.io.StdIn object Keywords { val Define = "define" val True = "true" val False = "false" val If = "if" val Then = "then" val Else = "else" val Return = "return" val Pass = "pass" val Conj = ";" val OpenParen = "(" val CloseParen = ")" val OpenBrack = "{" val CloseBrack = "}" val Comma = "," val Plus = "+" val Minus = "-" val Times = "*" val Divide = "/" val Pow = "**" val And = "&&" val Or = "||" val Xor = "^^" val Not = "!" val Equals = "==" val NotEquals = "!=" val Assignment = "=" } //--------------------------------------------------------------------------------- sealed abstract class Op case object Plus extends Op case object Minus extends Op case object Times extends Op case object Divide extends Op case object Pow extends Op case object And extends Op case object Or extends Op case object Xor extends Op case object Not extends Op case object Equals extends Op case object NotEquals extends Op case object Assignment extends Op //--------------------------------------------------------------------------------- sealed abstract class Term case object TrueTerm extends Term case object FalseTerm extends Term case class FloatTerm(value : Float) extends Term case class StringTerm(value : String) extends Term case class Identifier(name : String) extends Term //--------------------------------------------------------------------------------- sealed abstract class Expression case class TermExp(term : Term) extends Expression case class UnaryOp(op : Op, exp : Expression) extends Expression case class BinaryOp(op : Op, left : Expression, right : Expression) extends Expression case class FuncApp(funcName : Term, args : List[Expression]) extends Expression //--------------------------------------------------------------------------------- sealed abstract class Statement case class ExpressionStatement(exp : Expression) extends Statement case class Pass() extends Statement case class Return(value : Expression) extends Statement case class AssignmentVar(variable : Term, exp : Expression) extends Statement case class IfThenElse(testBody : Expression, thenBody : Statement, elseBody : Statement) extends Statement case class Conjunction(left : Statement, right : Statement) extends Statement case class AssignmentFunc(functionName : Term, args : List[Term], body : Statement) extends Statement //--------------------------------------------------------------------------------- class myParser extends JavaTokenParsers { val keywordMap : Map[String, Op] = Map( Keywords.Plus -> Plus, Keywords.Minus -> Minus, Keywords.Times -> Times, Keywords.Divide -> Divide, Keywords.Pow -> Pow, Keywords.And -> And, Keywords.Or -> Or, Keywords.Xor -> Xor, Keywords.Not -> Not, Keywords.Equals -> Equals, Keywords.NotEquals -> NotEquals, Keywords.Assignment -> Assignment ) def floatTerm : Parser[Term] = decimalNumber ^^ { case x => FloatTerm( x.toFloat ) } def stringTerm : Parser[Term] = stringLiteral ^^ { case str => StringTerm(str) } def identifier : Parser[Term] = ident ^^ { case value => Identifier(value) } def boolTerm : Parser[Term] = (Keywords.True | Keywords.False) ^^ { case Keywords.True => TrueTerm case Keywords.False => FalseTerm } def simpleTerm : Parser[Expression] = (boolTerm | floatTerm | stringTerm) ^^ { case term => TermExp(term) } def argument = expression def arguments_aux : Parser[List[Expression]] = (argument <~ Keywords.Comma) ~ arguments ^^ { case arg ~ argList => arg :: argList } def arguments = arguments_aux | { argument ^^ { case arg => List(arg) } } def funcAppArgs : Parser[List[Expression]] = funcEmptyArgs | ( Keywords.OpenParen ~> arguments <~ Keywords.CloseParen ^^ { case args => args.foldRight(List[Expression]()) ( (a,b) => a :: b ) } ) def funcApp = identifier ~ funcAppArgs ^^ { case funcName ~ argList => FuncApp(funcName, argList) } def variableTerm : Parser[Expression] = identifier ^^ { case name => TermExp(name) } def atomic_expression = simpleTerm | funcApp | variableTerm def paren_expression : Parser[Expression] = Keywords.OpenParen ~> expression <~ Keywords.CloseParen def unary_operation : Parser[String] = Keywords.Not def unary_expression : Parser[Expression] = operation(0) ~ expression(0) ^^ { case op ~ exp => UnaryOp(keywordMap(op), exp) } def operation(precedence : Int) : Parser[String] = precedence match { case 0 => Keywords.Not case 1 => Keywords.Pow case 2 => Keywords.Times | Keywords.Divide | Keywords.And case 3 => Keywords.Plus | Keywords.Minus | Keywords.Or | Keywords.Xor case 4 => Keywords.Equals | Keywords.NotEquals case _ => throw new Exception("No operations with this precedence.") } def binary_expression(precedence : Int) : Parser[Expression] = precedence match { case 0 => throw new Exception("No operation with zero precedence.") case n => (expression (n-1)) ~ operation(n) ~ (expression (n)) ^^ { case left ~ op ~ right => BinaryOp(keywordMap(op), left, right) } } def expression(precedence : Int) : Parser[Expression] = precedence match { case 0 => unary_expression | paren_expression | atomic_expression case n => binary_expression(n) | expression(n-1) } def expression : Parser[Expression] = expression(4) def expressionStmt : Parser[Statement] = expression ^^ { case exp => ExpressionStatement(exp) } def assignment : Parser[Statement] = (identifier <~ Keywords.Assignment) ~ expression ^^ { case varName ~ exp => AssignmentVar(varName, exp) } def ifthen : Parser[Statement] = ((Keywords.If ~ Keywords.OpenParen) ~> expression <~ Keywords.CloseParen) ~ ((Keywords.Then ~ Keywords.OpenBrack) ~> statements <~ Keywords.CloseBrack) ^^ { case ifBody ~ thenBody => IfThenElse(ifBody, thenBody, Pass()) } def ifthenelse : Parser[Statement] = ((Keywords.If ~ Keywords.OpenParen) ~> expression <~ Keywords.CloseParen) ~ ((Keywords.Then ~ Keywords.OpenBrack) ~> statements <~ Keywords.CloseBrack) ~ ((Keywords.Else ~ Keywords.OpenBrack) ~> statements <~ Keywords.CloseBrack) ^^ { case ifBody ~ thenBody ~ elseBody => IfThenElse(ifBody, thenBody, elseBody) } def pass : Parser[Statement] = Keywords.Pass ^^^ { Pass() } def returnStmt : Parser[Statement] = Keywords.Return ~> expression ^^ { case exp => Return(exp) } def statement : Parser[Statement] = ((pass | returnStmt | assignment | expressionStmt) <~ Keywords.Conj) | ifthenelse | ifthen def statements_aux : Parser[Statement] = statement ~ statements ^^ { case st ~ sts => Conjunction(st, sts) } def statements : Parser[Statement] = statements_aux | statement def funcDefBody : Parser[Statement] = Keywords.OpenBrack ~> statements <~ Keywords.CloseBrack def funcEmptyArgs = Keywords.OpenParen ~ Keywords.CloseParen ^^^ { List() } def funcDefArgs : Parser[List[Term]] = funcEmptyArgs | Keywords.OpenParen ~> repsep(identifier, Keywords.Comma) <~ Keywords.CloseParen ^^ { case args => args.foldRight(List[Term]()) ( (a,b) => a :: b ) } def funcDef : Parser[Statement] = (Keywords.Define ~> identifier) ~ funcDefArgs ~ funcDefBody ^^ { case funcName ~ funcArgs ~ body => AssignmentFunc(funcName, funcArgs, body) } def funcDefAndStatement : Parser[Statement] = funcDef | statement def funcDefAndStatements_aux : Parser[Statement] = funcDefAndStatement ~ funcDefAndStatements ^^ { case stmt ~ stmts => Conjunction(stmt, stmts) } def funcDefAndStatements : Parser[Statement] = funcDefAndStatements_aux | funcDefAndStatement def parseProgram : Parser[Statement] = funcDefAndStatements def eval(input : String) = { parseAll(parseProgram, input) match { case Success(result, _) => result case Failure(m, _) => println(m) case _ => println("") } } } object Parser { def main(args : Array[String]) { val x : myParser = new myParser() println(args(0)) val lines = scala.io.Source.fromFile(args(0)).mkString println(x.eval(lines)) } } The problem is, when I run the parser on the following example it works fine: define foo(a) { if (!h(IM) && a) then { return 0; } if (a() && !h()) then { return 0; } } But when I add threes characters in the first if statement, it runs out of memory. This is absolutely blowing my mind. Can anyone help? (I suspect it has to do with repsep, but I am not sure.) define foo(a) { if (!h(IM) && a(1)) then { return 0; } if (a() && !h()) then { return 0; } } EDIT: Any constructive comments about my Scala style is also appreciated.

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• WCF timeout exception detailed investigation

  - by Jason Kealey

  We have an application that has a WCF service (*.svc) running on IIS7 and various clients querying the service. The server is running Win 2008 Server. The clients are running either Windows 2008 Server or Windows 2003 server. I am getting the following exception, which I have seen can in fact be related to a large number of potential WCF issues. System.TimeoutException: The request channel timed out while waiting for a reply after 00:00:59.9320000. Increase the timeout value passed to the call to Request or increase the SendTimeout value on the Binding. The time allotted to this operation may have been a portion of a longer timeout. ---> System.TimeoutException: The HTTP request to 'http://www.domain.com/WebServices/myservice.svc/gzip' has exceeded the allotted timeout of 00:01:00. The time allotted to this operation may have been a portion of a longer timeout. I have increased the timeout to 30min and the error still occurred. This tells me that something else is at play, because the quantity of data could never take 30min to upload or download. The error comes and goes. At the moment, it is more frequent. It does not seem to matter if I have 3 clients running simultaneously or 100, it still occurs once in a while. Most of the time, there are no timeouts but I still get a few per hour. The error comes from any of the methods that are invoked. One of these methods does not have parameters and returns a bit of data. Another takes in lots of data as a parameter but executes asynchronously. The errors always originate from the client and never reference any code on the server in the stack trace. It always ends with: at System.Net.HttpWebRequest.GetResponse() at System.ServiceModel.Channels.HttpChannelFactory.HttpRequestChannel.HttpChannelRequest.WaitForReply(TimeSpan timeout) On the server: I've tried (and currently have) the following binding settings: maxBufferSize="2147483647" maxReceivedMessageSize="2147483647" maxBufferPoolSize="2147483647" It does not seem to have an impact. I've tried (and currently have) the following throttling settings: <serviceThrottling maxConcurrentCalls="1500" maxConcurrentInstances="1500" maxConcurrentSessions="1500"/> It does not seem to have an impact. I currently have the following settings for the WCF service. [ServiceBehavior(InstanceContextMode = InstanceContextMode.Single, ConcurrencyMode = ConcurrencyMode.Single)] I ran with ConcurrencyMode.Multiple for a while, and the error still occurred. I've tried restarting IIS, restarting my underlying SQL Server, restarting the machine. All of these don't seem to have an impact. I've tried disabling the Windows firewall. It does not seem to have an impact. On the client, I have these settings: maxReceivedMessageSize="2147483647" <system.net> <connectionManagement> <add address="*" maxconnection="16"/> </connectionManagement> </system.net> My client closes its connections: var client = new MyClient(); try { return client.GetConfigurationOptions(); } finally { client.Close(); } I have changed the registry settings to allow more outgoing connections: MaxConnectionsPerServer=24, MaxConnectionsPer1_0Server=32. I have now just recently tried SvcTraceViewer.exe. I managed to catch one exception on the client end. I see that its duration is 1 minute. Looking at the server side trace, I can see that the server is not aware of this exception. The maximum duration I can see is 10 seconds. I have looked at active database connections using exec sp_who on the server. I only have a few (2-3). I have looked at TCP connections from one client using TCPview. It usually is around 2-3 and I have seen up to 5 or 6. Simply put, I am stumped. I have tried everything I could find, and must be missing something very simple that a WCF expert would be able to see. It is my gut feeling that something is blocking my clients at the low-level (TCP), before the server actually receives the message and/or that something is queuing the messages at the server level and never letting them process. If you have any performance counters I should look at, please let me know. (please indicate what values are bad, as some of these counters are hard to decypher). Also, how could I log the WCF message size? Finally, are there any tools our there that would allow me to test how many connections I can establish between my client and server (independently from my application) Thanks for your time! Extra information added June 20th: My WCF application does something similar to the following. while (true) { Step1GetConfigurationSettingsFromServerViaWCF(); // can change between calls Step2GetWorkUnitFromServerViaWCF(); DoWorkLocally(); // takes 5-15minutes. Step3SendBackResultsToServerViaWCF(); } Using WireShark, I did see that when the error occurs, I have a five TCP retransmissions followed by a TCP reset later on. My guess is the RST is coming from WCF killing the connection. The exception report I get is from Step3 timing out. I discovered this by looking at the tcp stream "tcp.stream eq 192". I then expanded my filter to "tcp.stream eq 192 and http and http.request.method eq POST" and saw 6 POSTs during this stream. This seemed odd, so I checked with another stream such as tcp.stream eq 100. I had three POSTs, which seems a bit more normal because I am doing three calls. However, I do close my connection after every WCF call, so I would have expected one call per stream (but I don't know much about TCP). Investigating a bit more, I dumped the http packet load to disk to look at what these six calls where. 1) Step3 2) Step1 3) Step2 4) Step3 - corrupted 5) Step1 6) Step2 My guess is two concurrent clients are using the same connection, that is why I saw duplicates. However, I still have a few more issues that I can't comprehend: a) Why is the packet corrupted? Random network fluke - maybe? The load is gzipped using this sample code: http://msdn.microsoft.com/en-us/library/ms751458.aspx - Could the code be buggy once in a while when used concurrently? I should test without the gzip library. b) Why would I see step 1 & step 2 running AFTER the corrupted operation timed out? It seems to me as if these operations should not have occurred. Maybe I am not looking at the right stream because my understanding of TCP is flawed. I have other streams that occur at the same time. I should investigate other streams - a quick glance at streams 190-194 show that the Step3 POST have proper payload data (not corrupted). Pushing me to look at the gzip library again.

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• Ideas for multiplatform encrypted java mobile storage system

  - by Fernando Miguélez

  Objective I am currently designing the API for a multiplatform storage system that would offer same interface and capabilities accross following supported mobile Java Platforms: J2ME. Minimum configuration/profile CLDC 1.1/MIDP 2.0 with support for some necessary JSRs (JSR-75 for file storage). Android. No minimum platform version decided yet, but rather likely could be API level 7. Blackberry. It would use the same base source of J2ME but taking advantage of some advaced capabilities of the platform. No minimum configuration decided yet (maybe 4.6 because of 64 KB limitation for RMS on 4.5). Basically the API would sport three kind of stores: Files. These would allow standard directory/file manipulation (read/write through streams, create, mkdir, etc.). Preferences. It is a special store that handles properties accessed through keys (Similar to plain old java properties file but supporting some improvements such as different value data types such as SharedPreferences on Android platform) Local Message Queues. This store would offer basic message queue functionality. Considerations Inspired on JSR-75, all types of stores would be accessed in an uniform way by means of an URL following RFC 1738 conventions, but with custom defined prefixes (i.e. "file://" for files, "prefs://" for preferences or "queue://" for message queues). The address would refer to a virtual location that would be mapped to a physical storage object by each mobile platform implementation. Only files would allow hierarchical storage (folders) and access to external extorage memory cards (by means of a unit name, the same way as in JSR-75, but that would not change regardless of underlying platform). The other types would only support flat storage. The system should also support a secure version of all basic types. The user would indicate it by prefixing "s" to the URL (i.e. "sfile://" instead of "file://"). The API would only require one PIN (introduced only once) to access any kind of secure object types. Implementation issues For the implementation of both plaintext and encrypted stores, I would use the functionality available on the underlying platforms: Files. These are available on all platforms (J2ME only with JSR-75, but it is mandatory for our needs). The abstract File to actual File mapping is straight except for addressing issues. RMS. This type of store available on J2ME (and Blackberry) platforms is convenient for Preferences and maybe Message Queues (though depending on performance or size requirements these could be implemented by means of normal files). SharedPreferences. This type of storage, only available on Android, would match Preferences needs. SQLite databases. This could be used for message queues on Android (and maybe Blackberry). When it comes to encryption some requirements should be met: To ease the implementation it will be carried out on read/write operations basis on streams (for files), RMS Records, SharedPreferences key-value pairs, SQLite database columns. Every underlying storage object should use the same encryption key. Handling of encrypted stores should be the same as the unencrypted counterpart. The only difference (from the user point of view) accessing an encrypted store would be the addressing. The user PIN provides access to any secure storage object, but the change of it would not require to decrypt/re-encrypt all the encrypted data. Cryptographic capabilities of underlying platform should be used whenever it is possible, so we would use: J2ME: SATSA-CRYPTO if it is available (not mandatory) or lightweight BoncyCastle cryptographic framework for J2ME. Blackberry: RIM Cryptographic API or BouncyCastle Android: JCE with integraced cryptographic provider (BouncyCastle?) Doubts Having reached this point I was struck by some doubts about what solution would be more convenient, taking into account the limitation of the plataforms. These are some of my doubts: Encryption Algorithm for data. Would AES-128 be strong and fast enough? What alternatives for such scenario would you suggest? Encryption Mode. I have read about the weakness of ECB encryption versus CBC, but in this case the first would have the advantage of random access to blocks, which is interesting for seek functionality on files. What type of encryption mode would you choose instead? Is stream encryption suitable for this case? Key generation. There could be one key generated for each storage object (file, RMS RecordStore, etc.) or just use one for all the objects of the same type. The first seems "safer", though it would require some extra space on device. In your opinion what would the trade-offs of each? Key storage. For this case using a standard JKS (or PKCS#12) KeyStore file could be suited to store encryption keys, but I could also define a smaller structure (encryption-transformation / key data / checksum) that could be attached to each storage store (i.e. using addition files with the same name and special extension for plain files or embedded inside other types of objects such as RMS Record Stores). What approach would you prefer? And when it comes to using a standard KeyStore with multiple-key generation (given this is your preference), would it be better to use a record-store per storage object or just a global KeyStore keeping all keys (i.e. using the URL identifier of abstract storage object as alias)? Master key. The use of a master key seems obvious. This key should be protected by user PIN (introduced only once) and would allow access to the rest of encryption keys (they would be encrypted by means of this master key). Changing the PIN would only require to reencrypt this key and not all the encrypted data. Where would you keep it taking into account that if this got lost all data would be no further accesible? What further considerations should I take into account? Platform cryptography support. Do SATSA-CRYPTO-enabled J2ME phones really take advantage of some dedicated hardware acceleration (or other advantage I have not foreseen) and would this approach be prefered (whenever possible) over just BouncyCastle implementation? For the same reason is RIM Cryptographic API worth the license cost over BouncyCastle? Any comments, critics, further considerations or different approaches are welcome.

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• g++ SSE intrinsics dilemma - value from intrinsic "saturates"

  - by Sriram

  Hi, I wrote a simple program to implement SSE intrinsics for computing the inner product of two large (100000 or more elements) vectors. The program compares the execution time for both, inner product computed the conventional way and using intrinsics. Everything works out fine, until I insert (just for the fun of it) an inner loop before the statement that computes the inner product. Before I go further, here is the code: //this is a sample Intrinsics program to compute inner product of two vectors and compare Intrinsics with traditional method of doing things. #include <iostream> #include <iomanip> #include <xmmintrin.h> #include <stdio.h> #include <time.h> #include <stdlib.h> using namespace std; typedef float v4sf __attribute__ ((vector_size(16))); double innerProduct(float* arr1, int len1, float* arr2, int len2) { //assume len1 = len2. float result = 0.0; for(int i = 0; i < len1; i++) { for(int j = 0; j < len1; j++) { result += (arr1[i] * arr2[i]); } } //float y = 1.23e+09; //cout << "y = " << y << endl; return result; } double sse_v4sf_innerProduct(float* arr1, int len1, float* arr2, int len2) { //assume that len1 = len2. if(len1 != len2) { cout << "Lengths not equal." << endl; exit(1); } /*steps: * 1. load a long-type (4 float) into a v4sf type data from both arrays. * 2. multiply the two. * 3. multiply the same and store result. * 4. add this to previous results. */ v4sf arr1Data, arr2Data, prevSums, multVal, xyz; //__builtin_ia32_xorps(prevSums, prevSums); //making it equal zero. //can explicitly load 0 into prevSums using loadps or storeps (Check). float temp[4] = {0.0, 0.0, 0.0, 0.0}; prevSums = __builtin_ia32_loadups(temp); float result = 0.0; for(int i = 0; i < (len1 - 3); i += 4) { for(int j = 0; j < len1; j++) { arr1Data = __builtin_ia32_loadups(&arr1[i]); arr2Data = __builtin_ia32_loadups(&arr2[i]); //store the contents of two arrays. multVal = __builtin_ia32_mulps(arr1Data, arr2Data); //multiply. xyz = __builtin_ia32_addps(multVal, prevSums); prevSums = xyz; } } //prevSums will hold the sums of 4 32-bit floating point values taken at a time. Individual entries in prevSums also need to be added. __builtin_ia32_storeups(temp, prevSums); //store prevSums into temp. cout << "Values of temp:" << endl; for(int i = 0; i < 4; i++) cout << temp[i] << endl; result += temp[0] + temp[1] + temp[2] + temp[3]; return result; } int main() { clock_t begin, end; int length = 100000; float *arr1, *arr2; double result_Conventional, result_Intrinsic; // printStats("Allocating memory."); arr1 = new float[length]; arr2 = new float[length]; // printStats("End allocation."); srand(time(NULL)); //init random seed. // printStats("Initializing array1 and array2"); begin = clock(); for(int i = 0; i < length; i++) { // for(int j = 0; j < length; j++) { // arr1[i] = rand() % 10 + 1; arr1[i] = 2.5; // arr2[i] = rand() % 10 - 1; arr2[i] = 2.5; // } } end = clock(); cout << "Time to initialize array1 and array2 = " << ((double) (end - begin)) / CLOCKS_PER_SEC << endl; // printStats("Finished initialization."); // printStats("Begin inner product conventionally."); begin = clock(); result_Conventional = innerProduct(arr1, length, arr2, length); end = clock(); cout << "Time to compute inner product conventionally = " << ((double) (end - begin)) / CLOCKS_PER_SEC << endl; // printStats("End inner product conventionally."); // printStats("Begin inner product using Intrinsics."); begin = clock(); result_Intrinsic = sse_v4sf_innerProduct(arr1, length, arr2, length); end = clock(); cout << "Time to compute inner product with intrinsics = " << ((double) (end - begin)) / CLOCKS_PER_SEC << endl; //printStats("End inner product using Intrinsics."); cout << "Results: " << endl; cout << " result_Conventional = " << result_Conventional << endl; cout << " result_Intrinsics = " << result_Intrinsic << endl; return 0; } I use the following g++ invocation to build this: g++ -W -Wall -O2 -pedantic -march=i386 -msse intrinsics_SSE_innerProduct.C -o innerProduct Each of the loops above, in both the functions, runs a total of N^2 times. However, given that arr1 and arr2 (the two floating point vectors) are loaded with a value 2.5, the length of the array is 100,000, the result in both cases should be 6.25e+10. The results I get are: Results: result_Conventional = 6.25e+10 result_Intrinsics = 5.36871e+08 This is not all. It seems that the value returned from the function that uses intrinsics "saturates" at the value above. I tried putting other values for the elements of the array and different sizes too. But it seems that any value above 1.0 for the array contents and any size above 1000 meets with the same value we see above. Initially, I thought it might be because all operations within SSE are in floating point, but floating point should be able to store a number that is of the order of e+08. I am trying to see where I could be going wrong but cannot seem to figure it out. I am using g++ version: g++ (GCC) 4.4.1 20090725 (Red Hat 4.4.1-2). Any help on this is most welcome. Thanks, Sriram.

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• Form File Upload with other TextBox Inputs + Creating Custom Form Action attribute

  - by Jonathan Stowell

  Hi All, I am attempting to create a form where a user is able to enter your typical form values textboxes etc, but also upload a file as part of the form submission. This is my View code it can be seen that the File upload is identified by the MCF id: <% using (Html.BeginForm("Create", "Problem", FormMethod.Post, new { id = "ProblemForm", enctype = "multipart/form-data" })) {%> <p> <label for="StudentEmail">Student Email (*)</label> <br /> <%= Html.TextBox("StudentEmail", Model.Problem.StudentEmail, new { size = "30", maxlength=26 })%> <%= Html.ValidationMessage("StudentEmail", "*") %> </p> <p> <label for="Type">Communication Type (*)</label> <br /> <%= Html.DropDownList("Type") %> <%= Html.ValidationMessage("Type", "*") %> </p> <p> <label for="ProblemDateTime">Problem Date (*)</label> <br /> <%= Html.TextBox("ProblemDateTime", String.Format("{0:d}", Model.Problem.ProblemDateTime), new { maxlength = 10 })%> <%= Html.ValidationMessage("ProblemDateTime", "*") %> </p> <p> <label for="ProblemCategory">Problem Category (* OR Problem Outline)</label> <br /> <%= Html.DropDownList("ProblemCategory", null, "Please Select...")%> <%= Html.ValidationMessage("ProblemCategory", "*")%> </p> <p> <label for="ProblemOutline">Problem Outline (* OR Problem Category)</label> <br /> <%= Html.TextArea("ProblemOutline", Model.Problem.ProblemOutline, 6, 75, new { maxlength = 255 })%> <%= Html.ValidationMessage("ProblemOutline", "*") %> </p> <p> <label for="MCF">Mitigating Circumstance Form</label> <br /> <input id="MCF" type="file" /> <%= Html.ValidationMessage("MCF", "*") %> </p> <p> <label for="MCL">Mitigating Circumstance Level</label> <br /> <%= Html.DropDownList("MCL") %> <%= Html.ValidationMessage("MCL", "*") %> </p> <p> <label for="AbsentFrom">Date Absent From</label> <br /> <%= Html.TextBox("AbsentFrom", String.Format("{0:d}", Model.Problem.AbsentFrom), new { maxlength = 10 })%> <%= Html.ValidationMessage("AbsentFrom", "*") %> </p> <p> <label for="AbsentUntil">Date Absent Until</label> <br /> <%= Html.TextBox("AbsentUntil", String.Format("{0:d}", Model.Problem.AbsentUntil), new { maxlength = 10 })%> <%= Html.ValidationMessage("AbsentUntil", "*") %> </p> <p> <label for="AssessmentID">Assessment Extension</label> <br /> <%= Html.DropDownList("AssessmentID") %> <%= Html.ValidationMessage("AssessmentID", "*") %> <%= Html.TextBox("DateUntil", String.Format("{0:d}", Model.AssessmentExtension.DateUntil), new { maxlength = 16 })%> <%= Html.ValidationMessage("DateUntil", "*") %> </p> <p> <label for="Details">Assessment Extension Details</label> <br /> <%= Html.TextArea("Details", Model.AssessmentExtension.Details, 6, 75, new { maxlength = 255 })%> <%= Html.ValidationMessage("Details", "*") %> </p> <p> <label for="RequestedFollowUp">Requested Follow Up</label> <br /> <%= Html.TextBox("RequestedFollowUp", String.Format("{0:d}", Model.Problem.RequestedFollowUp), new { maxlength = 16 })%> <%= Html.ValidationMessage("RequestedFollowUp", "*") %> </p> <p> <label for="StaffEmail">Staff</label> <br /> <%= Html.ListBox("StaffEmail", Model.StaffEmail, new { @class = "multiselect" })%> <%= Html.ValidationMessage("StaffEmail", "*")%> </p> <p> <input class="button" type="submit" value="Create Problem" /> </p> This is my controller code: [AcceptVerbs(HttpVerbs.Post)] public ActionResult Create(Problem problem, AssessmentExtension assessmentExtension, Staff staffMember, HttpPostedFileBase file, string[] StaffEmail) { if (ModelState.IsValid) { try { Student student = studentRepository.GetStudent(problem.StudentEmail); Staff currentUserStaffMember = staffRepository.GetStaffWindowsLogon(User.Identity.Name); var fileName = Path.Combine(Request.MapPath("~/App_Data"), Path.GetFileName(file.FileName)); file.SaveAs(@"C:\Temp\" + fileName); if (problem.RequestedFollowUp.HasValue) { String meetingName = student.FirstName + " " + student.LastName + " " + "Mitigating Circumstance Meeting"; OutlookAppointment outlookAppointment = new OutlookAppointment(currentUserStaffMember.Email, meetingName, (DateTime)problem.RequestedFollowUp, (DateTime)problem.RequestedFollowUp.Value.AddMinutes(30)); } problemRepository.Add(problem); problemRepository.Save(); if (assessmentExtension.DateUntil != null) { assessmentExtension.ProblemID = problem.ProblemID; assessmentExtensionRepository.Add(assessmentExtension); assessmentExtensionRepository.Save(); } ProblemPrivacy problemPrivacy = new ProblemPrivacy(); problemPrivacy.ProblemID = problem.ProblemID; problemPrivacy.StaffEmail = currentUserStaffMember.Email; problemPrivacyRepository.Add(problemPrivacy); if (StaffEmail != null) { for (int i = 0; i < StaffEmail.Length; i++) { ProblemPrivacy probPrivacy = new ProblemPrivacy(); probPrivacy.ProblemID = problem.ProblemID; probPrivacy.StaffEmail = StaffEmail[i]; problemPrivacyRepository.Add(probPrivacy); } } problemPrivacyRepository.Save(); return RedirectToAction("Details", "Student", new { id = student.Email }); } catch { ModelState.AddRuleViolations(problem.GetRuleViolations()); } } return View(new ProblemFormViewModel(problem, assessmentExtension, staffMember)); } This form was working correctly before I had to switch to using a non-AJAX file upload, this was due to an issue with Flash when enabling Windows Authentication which I need to use. It appears that when I submit the form the file is not sent and I am unsure as to why? I have also been unsuccessful in finding an example online where a file upload is used in conjunction with other input types. Another query I have is that for Create, and Edit operations I have used a PartialView for my forms to make my application have higher code reuse. The form action is normally generated by just using: Html.BeginForm() And this populates the action depending on which Url is being used Edit or Create. However when populating HTML attributes you have to provide a action and controller value to pass HTML attributes. using (Html.BeginForm("Create", "Problem", FormMethod.Post, new { id = "ProblemForm", enctype = "multipart/form-data" })) Is it possible to somehow populate the action and controller value depending on the URL to maintain code reuse? Thinking about it whilst typing this I could set two values in the original controller action request view data and then just populate the value using the viewdata values? Any help on these two issues would be appreciated, I'm new to asp.net mvc :-) Thanks, Jon

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• Why does C qicksort function implementation works much slower (tape comparations, tape swapping) than bobble sort function?

  - by Artur Mustafin

  I'm going to implement a toy tape "mainframe" for a students, showing the quickness of "quicksort" class functions (recursive or not, does not really matters, due to the slow hardware, and well known stack reversal techniques) comparatively to the "bubblesort" function class, so, while I'm clear about the hardware implementation ans controllers, i guessed that quicksort function is much faster that other ones in terms of sequence, order and comparation distance (it is much faster to rewind the tape from the middle than from the very end, because of different speed of rewind). Unfortunately, this is not the true, this simple "bubble" code shows great improvements comparatively to the "quicksort" functions in terms of comparison distances, direction and number of comparisons and writes. So I have 3 questions: Does I have mistaken in my implememtation of quicksort function? Does I have mistaken in my implememtation of bubblesoft function? If not, why the "bubblesort" function is works much faster in (comparison and write operations) than "quicksort" function? I already have a "quicksort" function: void quicksort(float *a, long l, long r, const compare_function& compare) { long i=l, j=r, temp, m=(l+r)/2; if (l == r) return; if (l == r-1) { if (compare(a, l, r)) { swap(a, l, r); } return; } if (l < r-1) { while (1) { i = l; j = r; while (i < m && !compare(a, i, m)) i++; while (m < j && !compare(a, m, j)) j--; if (i >= j) { break; } swap(a, i, j); } if (l < m) quicksort(a, l, m, compare); if (m < r) quicksort(a, m, r, compare); return; } } and the kind of my own implememtation of the "bubblesort" function: void bubblesort(float *a, long l, long r, const compare_function& compare) { long i, j, k; if (l == r) { return; } if (l == r-1) { if (compare(a, l, r)) { swap(a, l, r); } return; } if (l < r-1) { while(l < r) { i = l; j = l; while (i < r) { i++; if (!compare(a, j, i)) { continue; } j = i; } if (l < j) { swap(a, l, j); } l++; i = r; k = r; while(l < i) { i--; if (!compare(a, i, k)) { continue; } k = i; } if (k < r) { swap(a, k, r); } r--; } return; } } I have used this sort functions in a test sample code, like this: #include <stdio.h> #include <stdlib.h> #include <math.h> #include <conio.h> long swap_count; long compare_count; typedef long (*compare_function)(float *, long, long ); typedef void (*sort_function)(float *, long , long , const compare_function& ); void init(float *, long ); void print(float *, long ); void sort(float *, long, const sort_function& ); void swap(float *a, long l, long r); long less(float *a, long l, long r); long greater(float *a, long l, long r); void bubblesort(float *, long , long , const compare_function& ); void quicksort(float *, long , long , const compare_function& ); void main() { int n; printf("n="); scanf("%d",&n); printf("\r\n"); long i; float *a = (float *)malloc(n*n*sizeof(float)); sort(a, n, &bubblesort); print(a, n); sort(a, n, &quicksort); print(a, n); free(a); } long less(float *a, long l, long r) { compare_count++; return *(a+l) < *(a+r) ? 1 : 0; } long greater(float *a, long l, long r) { compare_count++; return *(a+l) > *(a+r) ? 1 : 0; } void swap(float *a, long l, long r) { swap_count++; float temp; temp = *(a+l); *(a+l) = *(a+r); *(a+r) = temp; } float tg(float x) { return tan(x); } float ctg(float x) { return 1.0/tan(x); } void init(float *m,long n) { long i,j; for (i = 0; i < n; i++) { for (j=0; j< n; j++) { m[i + j*n] = tg(0.2*(i+1)) + ctg(0.3*(j+1)); } } } void print(float *m, long n) { long i, j; for(i = 0; i < n; i++) { for(j = 0; j < n; j++) { printf(" %5.1f", m[i + j*n]); } printf("\r\n"); } printf("\r\n"); } void sort(float *a, long n, const sort_function& sort) { long i, sort_compare = 0, sort_swap = 0; init(a,n); for(i = 0; i < n*n; i+=n) { if (fmod (i / n, 2) == 0) { compare_count = 0; swap_count = 0; sort(a, i, i+n-1, &less); if (swap_count == 0) { compare_count = 0; sort(a, i, i+n-1, &greater); } sort_compare += compare_count; sort_swap += swap_count; } } printf("compare=%ld\r\n", sort_compare); printf("swap=%ld\r\n", sort_swap); printf("\r\n"); }

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• Using Handlebars.js issue

  - by Roland

  I'm having a small issue when I'm compiling a template with Handlebars.js . I have a JSON text file which contains an big array with objects : Source ; and I'm using XMLHTTPRequest to get it and then parse it so I can use it when compiling the template. So far the template has the following structure : <div class="product-listing-wrapper"> <div class="product-listing"> <div class="left-side-content"> <div class="thumb-wrapper"> <img src="{{ThumbnailUrl}}"> </div> <div class="google-maps-wrapper"> <div class="google-coordonates-wrapper"> <div class="google-coordonates"> <p>{{LatLon.Lat}}</p> <p>{{LatLon.Lon}}</p> </div> </div> <div class="google-maps-button"> <a class="google-maps" href="#" data-latitude="{{LatLon.Lat}}" data-longitude="{{LatLon.Lon}}">Google Maps</a> </div> </div> </div> <div class="right-side-content"></div> </div> And the following block of code would be the way I'm handling the JS part : $(document).ready(function() { /* Default Javascript Options ~a javascript object which contains all the variables that will be passed to the cluster class */ var default_cluster_options = { animations : ['flash', 'bounce', 'shake', 'tada', 'swing', 'wobble', 'wiggle', 'pulse', 'flip', 'flipInX', 'flipOutX', 'flipInY', 'flipOutY', 'fadeIn', 'fadeInUp', 'fadeInDown', 'fadeInLeft', 'fadeInRight', 'fadeInUpBig', 'fadeInDownBig', 'fadeInLeftBig', 'fadeInRightBig', 'fadeOut', 'fadeOutUp', 'fadeOutDown', 'fadeOutLeft', 'fadeOutRight', 'fadeOutUpBig', 'fadeOutDownBig', 'fadeOutLeftBig', 'fadeOutRightBig', 'bounceIn', 'bounceInUp', 'bounceInDown', 'bounceInLeft', 'bounceInRight', 'bounceOut', 'bounceOutUp', 'bounceOutDown', 'bounceOutLeft', 'bounceOutRight', 'rotateIn', 'rotateInDownLeft', 'rotateInDownRight', 'rotateInUpLeft', 'rotateInUpRight', 'rotateOut', 'rotateOutDownLeft', 'rotateOutDownRight', 'rotateOutUpLeft', 'rotateOutUpRight', 'lightSpeedIn', 'lightSpeedOut', 'hinge', 'rollIn', 'rollOut'], json_data_url : 'data.json', template_data_url : 'template.php', base_maps_api_url : 'https://maps.googleapis.com/maps/api/js?sensor=false', cluser_wrapper_id : '#content-wrapper', maps_wrapper_class : '.google-maps', }; /* Cluster ~main class, handles all javascript operations */ var Cluster = function(environment, cluster_options) { var self = this; this.options = $.extend({}, default_cluster_options, cluster_options); this.environment = environment; this.animations = this.options.animations; this.json_data_url = this.options.json_data_url; this.template_data_url = this.options.template_data_url; this.base_maps_api_url = this.options.base_maps_api_url; this.cluser_wrapper_id = this.options.cluser_wrapper_id; this.maps_wrapper_class = this.options.maps_wrapper_class; this.test_environment_mode(this.environment); this.initiate_environment(); this.test_xmlhttprequest_availability(); this.initiate_gmaps_lib_load(self.base_maps_api_url); this.initiate_data_processing(); }; /* Test Environment Mode ~adds a modernizr test which looks wheater the cluster class is initiated in development or not */ Cluster.prototype.test_environment_mode = function(environment) { var self = this; return Modernizr.addTest('test_environment', function() { return (typeof environment !== 'undefined' && environment !== null && environment === "Development") ? true : false; }); }; /* Test XMLHTTPRequest Availability ~adds a modernizr test which looks wheater the xmlhttprequest class is available or not in the browser, exception makes IE */ Cluster.prototype.test_xmlhttprequest_availability = function() { return Modernizr.addTest('test_xmlhttprequest', function() { return (typeof window.XMLHttpRequest === 'undefined' || window.XMLHttpRequest === null) ? true : false; }); }; /* Initiate Environment ~depending on what the modernizr test returns it puts LESS in the development mode or not */ Cluster.prototype.initiate_environment = function() { return (Modernizr.test_environment) ? (less.env = "development", less.watch()) : true; }; Cluster.prototype.initiate_gmaps_lib_load = function(lib_url) { return Modernizr.load(lib_url); }; /* Initiate XHR Request ~prototype function that creates an xmlhttprequest for processing json data from an separate json text file */ Cluster.prototype.initiate_xhr_request = function(url, mime_type) { var request, data; var self = this; (Modernizr.test_xmlhttprequest) ? request = new ActiveXObject('Microsoft.XMLHTTP') : request = new XMLHttpRequest(); request.onreadystatechange = function() { if(request.readyState == 4 && request.status == 200) { data = request.responseText; } }; request.open("GET", url, false); request.overrideMimeType(mime_type); request.send(); return data; }; Cluster.prototype.initiate_google_maps_action = function() { var self = this; return $(this.maps_wrapper_class).each(function(index, element) { return $(element).on('click', function(ev) { var html = $('<div id="map-canvas" class="map-canvas"></div>'); var latitude = $(element).attr('data-latitude'); var longitude = $(element).attr('data-longitude'); log("LAT : " + latitude); log("LON : " + longitude); $.lightbox(html, { "width": 900, "height": 250, "onOpen" : function() { } }); ev.preventDefault(); }); }); }; Cluster.prototype.initiate_data_processing = function() { var self = this; var json_data = JSON.parse(self.initiate_xhr_request(self.json_data_url, 'application/json; charset=ISO-8859-1')); var source_data = self.initiate_xhr_request(self.template_data_url, 'text/html'); var template = Handlebars.compile(source_data); for(var i = 0; i < json_data.length; i++ ) { var result = template(json_data[i]); $(result).appendTo(self.cluser_wrapper_id); } self.initiate_google_maps_action(); }; /* Cluster ~initiate the cluster class */ var cluster = new Cluster("Development"); }); My problem would be that I don't think I'm iterating the JSON object right or I'm using the template the wrong way because if you check this link : http://rolandgroza.com/labs/valtech/ ; you will see that there are some numbers there ( which represents latitude and longitude ) but they are all the same and if you take only a brief look at the JSON object each number is different. So what am I doing wrong that it makes the same number repeat ? Or what should I do to fix it ? I must notice that I've just started working with templates so I have little knowledge it.

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• Handling inheritance with overriding efficiently

  - by Fyodor Soikin

  I have the following two data structures. First, a list of properties applied to object triples: Object1 Object2 Object3 Property Value O1 O2 O3 P1 "abc" O1 O2 O3 P2 "xyz" O1 O3 O4 P1 "123" O2 O4 O5 P1 "098" Second, an inheritance tree: O1 O2 O4 O3 O5 Or viewed as a relation: Object Parent O2 O1 O4 O2 O3 O1 O5 O3 O1 null The semantics of this being that O2 inherits properties from O1; O4 - from O2 and O1; O3 - from O1; and O5 - from O3 and O1, in that order of precedence. NOTE 1: I have an efficient way to select all children or all parents of a given object. This is currently implemented with left and right indexes, but hierarchyid could also work. This does not seem important right now. NOTE 2: I have tiggers in place that make sure that the "Object" column always contains all possible objects, even when they do not really have to be there (i.e. have no parent or children defined). This makes it possible to use inner joins rather than severely less effiecient outer joins. The objective is: Given a pair of (Property, Value), return all object triples that have that property with that value either defined explicitly or inherited from a parent. NOTE 1: An object triple (X,Y,Z) is considered a "parent" of triple (A,B,C) when it is true that either X = A or X is a parent of A, and the same is true for (Y,B) and (Z,C). NOTE 2: A property defined on a closer parent "overrides" the same property defined on a more distant parent. NOTE 3: When (A,B,C) has two parents - (X1,Y1,Z1) and (X2,Y2,Z2), then (X1,Y1,Z1) is considered a "closer" parent when: (a) X2 is a parent of X1, or (b) X2 = X1 and Y2 is a parent of Y1, or (c) X2 = X1 and Y2 = Y1 and Z2 is a parent of Z1 In other words, the "closeness" in ancestry for triples is defined based on the first components of the triples first, then on the second components, then on the third components. This rule establishes an unambigous partial order for triples in terms of ancestry. For example, given the pair of (P1, "abc"), the result set of triples will be: O1, O2, O3 -- Defined explicitly O1, O2, O5 -- Because O5 inherits from O3 O1, O4, O3 -- Because O4 inherits from O2 O1, O4, O5 -- Because O4 inherits from O2 and O5 inherits from O3 O2, O2, O3 -- Because O2 inherits from O1 O2, O2, O5 -- Because O2 inherits from O1 and O5 inherits from O3 O2, O4, O3 -- Because O2 inherits from O1 and O4 inherits from O2 O3, O2, O3 -- Because O3 inherits from O1 O3, O2, O5 -- Because O3 inherits from O1 and O5 inherits from O3 O3, O4, O3 -- Because O3 inherits from O1 and O4 inherits from O2 O3, O4, O5 -- Because O3 inherits from O1 and O4 inherits from O2 and O5 inherits from O3 O4, O2, O3 -- Because O4 inherits from O1 O4, O2, O5 -- Because O4 inherits from O1 and O5 inherits from O3 O4, O4, O3 -- Because O4 inherits from O1 and O4 inherits from O2 O5, O2, O3 -- Because O5 inherits from O1 O5, O2, O5 -- Because O5 inherits from O1 and O5 inherits from O3 O5, O4, O3 -- Because O5 inherits from O1 and O4 inherits from O2 O5, O4, O5 -- Because O5 inherits from O1 and O4 inherits from O2 and O5 inherits from O3 Note that the triple (O2, O4, O5) is absent from this list. This is because property P1 is defined explicitly for the triple (O2, O4, O5) and this prevents that triple from inheriting that property from (O1, O2, O3). Also note that the triple (O4, O4, O5) is also absent. This is because that triple inherits its value of P1="098" from (O2, O4, O5), because it is a closer parent than (O1, O2, O3). The straightforward way to do it is the following. First, for every triple that a property is defined on, select all possible child triples: select Children1.Id as O1, Children2.Id as O2, Children3.Id as O3, tp.Property, tp.Value from TriplesAndProperties tp -- Select corresponding objects of the triple inner join Objects as Objects1 on Objects1.Id = tp.O1 inner join Objects as Objects2 on Objects2.Id = tp.O2 inner join Objects as Objects3 on Objects3.Id = tp.O3 -- Then add all possible children of all those objects inner join Objects as Children1 on Objects1.Id [isparentof] Children1.Id inner join Objects as Children2 on Objects2.Id [isparentof] Children2.Id inner join Objects as Children3 on Objects3.Id [isparentof] Children3.Id But this is not the whole story: if some triple inherits the same property from several parents, this query will yield conflicting results. Therefore, second step is to select just one of those conflicting results: select * from ( select Children1.Id as O1, Children2.Id as O2, Children3.Id as O3, tp.Property, tp.Value, row_number() over( partition by Children1.Id, Children2.Id, Children3.Id, tp.Property order by Objects1.[depthInTheTree] descending, Objects2.[depthInTheTree] descending, Objects3.[depthInTheTree] descending ) as InheritancePriority from ... (see above) ) where InheritancePriority = 1 The window function row_number() over( ... ) does the following: for every unique combination of objects triple and property, it sorts all values by the ancestral distance from the triple to the parents that the value is inherited from, and then I only select the very first of the resulting list of values. A similar effect can be achieved with a GROUP BY and ORDER BY statements, but I just find the window function semantically cleaner (the execution plans they yield are identical). The point is, I need to select the closest of contributing ancestors, and for that I need to group and then sort within the group. And finally, now I can simply filter the result set by Property and Value. This scheme works. Very reliably and predictably. It has proven to be very powerful for the business task it implements. The only trouble is, it is awfuly slow. One might point out the join of seven tables might be slowing things down, but that is actually not the bottleneck. According to the actual execution plan I'm getting from the SQL Management Studio (as well as SQL Profiler), the bottleneck is the sorting. The problem is, in order to satisfy my window function, the server has to sort by Children1.Id, Children2.Id, Children3.Id, tp.Property, Parents1.[depthInTheTree] descending, Parents2.[depthInTheTree] descending, Parents3.[depthInTheTree] descending, and there can be no indexes it can use, because the values come from a cross join of several tables. EDIT: Per Michael Buen's suggestion (thank you, Michael), I have posted the whole puzzle to sqlfiddle here. One can see in the execution plan that the Sort operation accounts for 32% of the whole query, and that is going to grow with the number of total rows, because all the other operations use indexes. Usually in such cases I would use an indexed view, but not in this case, because indexed views cannot contain self-joins, of which there are six. The only way that I can think of so far is to create six copies of the Objects table and then use them for the joins, thus enabling an indexed view. Did the time come that I shall be reduced to that kind of hacks? The despair sets in.

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• c# Unable to open file for reading

  - by Maks

  I'm writing a program that uses FileSystemWatcher to monitor changes to a given directory, and when it recieves OnCreated or OnChanged event, it copies those created/changed files to a specified directorie(s). At first I had problems with the fact that OnChanged/OnCreated events can be sent twice (not acceptable in case it needed to process 500MB file) but I made a way around this and with what I'm REALLY STUCKED with is getting the following IOException: The process cannot access the file 'C:\Where are Photos\bookmarks (11).html' because it is being used by another process. Thus, preventing the program from copying all the files it should. So as I mentioned, when user uses this program he/she specifes monitored directory, when user copies/creates/changes file in that directory, program should get OnCreated/OnChanged event and then copy that file to few other directories. Above error happens in all casess, if user copies few files that needs to owerwrite other ones in folder being monitored or when copying bulk of several files or even sometimes when copying one file in a monitored directory. Whole program is quite big so I'm sending the most important parts. OnCreated: private void OnCreated(object source, FileSystemEventArgs e) { AddLogEntry(e.FullPath, "created", ""); // Update last access data if it's file so the same file doesn't // get processed twice because of sending another event. if (fileType(e.FullPath) == 2) { lastPath = e.FullPath; lastTime = DateTime.Now; } // serves no purpose now, it will be remove soon string fileName = GetFileName(e.FullPath); // copies file from source to few other directories Copy(e.FullPath, fileName); Console.WriteLine("OnCreated: " + e.FullPath); } OnChanged: private void OnChanged(object source, FileSystemEventArgs e) { // is it directory if (fileType(e.FullPath) == 1) return; // don't mind directory changes itself // Only if enough time has passed or if it's some other file // because two events can be generated int timeDiff = ((TimeSpan)(DateTime.Now - lastTime)).Seconds; if ((timeDiff < minSecsDiff) && (e.FullPath.Equals(lastPath))) { Console.WriteLine("-- skipped -- {0}, timediff: {1}", e.FullPath, timeDiff); return; } // Update last access data for above to work lastPath = e.FullPath; lastTime = DateTime.Now; // Only if size is changed, the rest will handle other handlers if (e.ChangeType == WatcherChangeTypes.Changed) { AddLogEntry(e.FullPath, "changed", ""); string fileName = GetFileName(e.FullPath); Copy(e.FullPath, fileName); Console.WriteLine("OnChanged: " + e.FullPath); } } fileType: private int fileType(string path) { if (Directory.Exists(path)) return 1; // directory else if (File.Exists(path)) return 2; // file else return 0; } Copy: private void Copy(string srcPath, string fileName) { foreach (string dstDirectoy in paths) { string eventType = "copied"; string error = "noerror"; string path = ""; string dirPortion = ""; // in case directory needs to be made if (srcPath.Length > fsw.Path.Length) { path = srcPath.Substring(fsw.Path.Length, srcPath.Length - fsw.Path.Length); int pos = path.LastIndexOf('\\'); if (pos != -1) dirPortion = path.Substring(0, pos); } if (fileType(srcPath) == 1) { try { Directory.CreateDirectory(dstDirectoy + path); //Directory.CreateDirectory(dstDirectoy + fileName); eventType = "created"; } catch (IOException e) { eventType = "error"; error = e.Message; } } else { try { if (!overwriteFile && File.Exists(dstDirectoy + path)) continue; // create new dir anyway even if it exists just to be sure Directory.CreateDirectory(dstDirectoy + dirPortion); // copy file from where event occured to all specified directories using (FileStream fsin = new FileStream(srcPath, FileMode.Open, FileAccess.Read, FileShare.Read)) { using (FileStream fsout = new FileStream(dstDirectoy + path, FileMode.Create, FileAccess.Write)) { byte[] buffer = new byte[32768]; int bytesRead = -1; while ((bytesRead = fsin.Read(buffer, 0, buffer.Length)) > 0) fsout.Write(buffer, 0, bytesRead); } } } catch (Exception e) { if ((e is IOException) && (overwriteFile == false)) { eventType = "skipped"; } else { eventType = "error"; error = e.Message; // attempt to find and kill the process locking the file. // failed, miserably System.Diagnostics.Process tool = new System.Diagnostics.Process(); tool.StartInfo.FileName = "handle.exe"; tool.StartInfo.Arguments = "\"" + srcPath + "\""; tool.StartInfo.UseShellExecute = false; tool.StartInfo.RedirectStandardOutput = true; tool.Start(); tool.WaitForExit(); string outputTool = tool.StandardOutput.ReadToEnd(); string matchPattern = @"(?<=\s+pid:\s+)\b(\d+)\b(?=\s+)"; foreach (Match match in Regex.Matches(outputTool, matchPattern)) { System.Diagnostics.Process.GetProcessById(int.Parse(match.Value)).Kill(); } Console.WriteLine("ERROR: {0}: [ {1} ]", e.Message, srcPath); } } } AddLogEntry(dstDirectoy + path, eventType, error); } } I checked everywhere in my program and whenever I use some file I use it in using block so even writing event to log (class for what I ommited since there is probably too much code already in post) wont lock the file, that is it shouldn't since all operations are using using statement block. I simply have no clue who's locking the file if not my program "copy" process from user through Windows or something else. Right now I have two possible "solutions" (I can't say they are clean solutions since they are hacks and as such not desireable). Since probably the problem is with fileType method (what else could lock the file?) I tried changing it to this, to simulate "blocking-until-ready-to-open" operation: fileType: private int fileType(string path) { FileStream fs = null; int ret = 0; bool run = true; if (Directory.Exists(path)) ret = 1; else { while (run) { try { fs = new FileStream(path, FileMode.Open); ret = 2; run = false; } catch (IOException) { } finally { if (fs != null) { fs.Close(); fs.Dispose(); } } } } return ret; } This is working as much as I could tell (test), but... it's hack, not to mention other deficients. The other "solution" I could try (I didn't test it yet) is using GC.Collect() somewhere at the end of fileType() method. Maybe even worse "solution" than previous one. Can someone pleas tell me, what on earth is locking the file, preventing it from opening and how can I fix that? What am I missing to see? Thanks in advance.

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• Linked List manipulation, issues retrieving data c++

  - by floatfil

  I'm trying to implement some functions to manipulate a linked list. The implementation is a template typename T and the class is 'List' which includes a 'head' pointer and also a struct: struct Node { // the node in a linked list T* data; // pointer to actual data, operations in T Node* next; // pointer to a Node }; Since it is a template, and 'T' can be any data, how do I go about checking the data of a list to see if it matches the data input into the function? The function is called 'retrieve' and takes two parameters, the data and a pointer: bool retrieve(T target, T*& ptr); // This is the prototype we need to use for the project "bool retrieve : similar to remove, but not removed from list. If there are duplicates in the list, the first one encountered is retrieved. Second parameter is unreliable if return value is false. E.g., " Employee target("duck", "donald"); success = company1.retrieve(target, oneEmployee); if (success) { cout << "Found in list: " << *oneEmployee << endl; } And the function is called like this: company4.retrieve(emp3, oneEmployee) So that when you cout *oneEmployee, you'll get the data of that pointer (in this case the data is of type Employee). (Also, this is assuming all data types have the apropriate overloaded operators) I hope this makes sense so far, but my issue is in comparing the data in the parameter and the data while going through the list. (The data types that we use all include overloads for equality operators, so oneData == twoData is valid) This is what I have so far: template <typename T> bool List<T>::retrieve(T target , T*& ptr) { List<T>::Node* dummyPtr = head; // point dummy pointer to what the list's head points to for(;;) { if (*dummyPtr->data == target) { // EDIT: it now compiles, but it breaks here and I get an Access Violation error. ptr = dummyPtr->data; // set the parameter pointer to the dummy pointer return true; // return true } else { dummyPtr = dummyPtr->next; // else, move to the next data node } } return false; } Here is the implementation for the Employee class: //-------------------------- constructor ----------------------------------- Employee::Employee(string last, string first, int id, int sal) { idNumber = (id >= 0 && id <= MAXID? id : -1); salary = (sal >= 0 ? sal : -1); lastName = last; firstName = first; } //-------------------------- destructor ------------------------------------ // Needed so that memory for strings is properly deallocated Employee::~Employee() { } //---------------------- copy constructor ----------------------------------- Employee::Employee(const Employee& E) { lastName = E.lastName; firstName = E.firstName; idNumber = E.idNumber; salary = E.salary; } //-------------------------- operator= --------------------------------------- Employee& Employee::operator=(const Employee& E) { if (&E != this) { idNumber = E.idNumber; salary = E.salary; lastName = E.lastName; firstName = E.firstName; } return *this; } //----------------------------- setData ------------------------------------ // set data from file bool Employee::setData(ifstream& inFile) { inFile >> lastName >> firstName >> idNumber >> salary; return idNumber >= 0 && idNumber <= MAXID && salary >= 0; } //------------------------------- < ---------------------------------------- // < defined by value of name bool Employee::operator<(const Employee& E) const { return lastName < E.lastName || (lastName == E.lastName && firstName < E.firstName); } //------------------------------- <= ---------------------------------------- // < defined by value of inamedNumber bool Employee::operator<=(const Employee& E) const { return *this < E || *this == E; } //------------------------------- > ---------------------------------------- // > defined by value of name bool Employee::operator>(const Employee& E) const { return lastName > E.lastName || (lastName == E.lastName && firstName > E.firstName); } //------------------------------- >= ---------------------------------------- // < defined by value of name bool Employee::operator>=(const Employee& E) const { return *this > E || *this == E; } //----------------- operator == (equality) ---------------- // if name of calling and passed object are equal, // return true, otherwise false // bool Employee::operator==(const Employee& E) const { return lastName == E.lastName && firstName == E.firstName; } //----------------- operator != (inequality) ---------------- // return opposite value of operator== bool Employee::operator!=(const Employee& E) const { return !(*this == E); } //------------------------------- << --------------------------------------- // display Employee object ostream& operator<<(ostream& output, const Employee& E) { output << setw(4) << E.idNumber << setw(7) << E.salary << " " << E.lastName << " " << E.firstName << endl; return output; } I will include a check for NULL pointer but I just want to get this working and will test it on a list that includes the data I am checking. Thanks to whoever can help and as usual, this is for a course so I don't expect or want the answer, but any tips as to what might be going wrong will help immensely!

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• Building applications with WPF, MVVM and Prism(aka CAG)

  - by skjagini

  In this article I am going to walk through an application using WPF and Prism (aka composite application guidance, CAG) which simulates engaging a taxi (cab).  The rules are simple, the app would have3 screens A login screen to authenticate the user An information screen. A screen to engage the cab and roam around and calculating the total fare Metered Rate of Fare The meter is required to be engaged when a cab is occupied by anyone $3.00 upon entry $0.35 for each additional unit The unit fare is: one-fifth of a mile, when the cab is traveling at 6 miles an hour or more; or 60 seconds when not in motion or traveling at less than 12 miles per hour. Night surcharge of $.50 after 8:00 PM & before 6:00 AM Peak hour Weekday Surcharge of $1.00 Monday - Friday after 4:00 PM & before 8:00 PM New York State Tax Surcharge of $.50 per ride. Example: Friday (2010-10-08) 5:30pm Start at Lexington Ave & E 57th St End at Irving Pl & E 15th St Start = $3.00 Travels 2 miles at less than 6 mph for 15 minutes = $3.50 Travels at more than 12 mph for 5 minutes = $1.75 Peak hour Weekday Surcharge = $1.00 (ride started at 5:30 pm) New York State Tax Surcharge = $0.50 Before we dive into the app, I would like to give brief description about the framework.  If you want to jump on to the source code, scroll all the way to the end of the post. MVVM MVVM pattern is in no way related to the usage of PRISM in your application and should be considered if you are using WPF irrespective of PRISM or not. Lets say you are not familiar with MVVM, your typical UI would involve adding some UI controls like text boxes, a button, double clicking on the button,  generating event handler, calling a method from business layer and updating the user interface, it works most of the time for developing small scale applications. The problem with this approach is that there is some amount of code specific to business logic wrapped in UI specific code which is hard to unit test it, mock it and MVVM helps to solve the exact problem. MVVM stands for Model(M) – View(V) – ViewModel(VM),  based on the interactions with in the three parties it should be called VVMM,  MVVM sounds more like MVC (Model-View-Controller) so the name. Why it should be called VVMM: View – View Model - Model WPF allows to create user interfaces using XAML and MVVM takes it to the next level by allowing complete separation of user interface and business logic. In WPF each view will have a property, DataContext when set to an instance of a class (which happens to be your view model) provides the data the view is interested in, i.e., view interacts with view model and at the same time view model interacts with view through DataContext. Sujith, if view and view model are interacting directly with each other how does MVVM is helping me separation of concerns? Well, the catch is DataContext is of type Object, since it is of type object view doesn’t know exact type of view model allowing views and views models to be loosely coupled. View models aggregate data from models (data access layer, services, etc) and make it available for views through properties, methods etc, i.e., View Models interact with Models. PRISM Prism is provided by Microsoft Patterns and Practices team and it can be downloaded from codeplex for source code,  samples and documentation on msdn.  The name composite implies, to compose user interface from different modules (views) without direct dependencies on each other, again allowing  loosely coupled development. Well Sujith, I can already do that with user controls, why shall I learn another framework?  That’s correct, you can decouple using user controls, but you still have to manage some amount of coupling, like how to do you communicate between the controls, how do you subscribe/unsubscribe, loading/unloading views dynamically. Prism is not a replacement for user controls, provides the following features which greatly help in designing the composite applications. Dependency Injection (DI)/ Inversion of Control (IoC) Modules Regions Event Aggregator  Commands Simply put, MVVM helps building a single view and Prism helps building an application using the views There are other open source alternatives to Prism, like MVVMLight, Cinch, take a look at them as well. Lets dig into the source code.  1. Solution The solution is made of the following projects Framework: Holds the common functionality in building applications using WPF and Prism TaxiClient: Start up project, boot strapping and app styling TaxiCommon: Helps with the business logic TaxiModules: Holds the meat of the application with views and view models TaxiTests: To test the application 2. DI / IoC Dependency Injection (DI) as the name implies refers to injecting dependencies and Inversion of Control (IoC) means the calling code has no direct control on the dependencies, opposite of normal way of programming where dependencies are passed by caller, i.e inversion; aside from some differences in terminology the concept is same in both the cases. The idea behind DI/IoC pattern is to reduce the amount of direct coupling between different components of the application, the higher the dependency the more tightly coupled the application resulting in code which is hard to modify, unit test and mock.  Initializing Dependency Injection through BootStrapper TaxiClient is the starting project of the solution and App (App.xaml)  is the starting class that gets called when you run the application. From the App’s OnStartup method we will invoke BootStrapper.   namespace TaxiClient { /// <summary> /// Interaction logic for App.xaml /// </summary> public partial class App : Application { protected override void OnStartup(StartupEventArgs e) { base.OnStartup(e);   (new BootStrapper()).Run(); } } } BootStrapper is your contact point for initializing the application including dependency injection, creating Shell and other frameworks. We are going to use Unity for DI and there are lot of open source DI frameworks like Spring.Net, StructureMap etc with different feature set  and you can choose a framework based on your preferences. Note that Prism comes with in built support for Unity, for example we are deriving from UnityBootStrapper in our case and for any other DI framework you have to extend the Prism appropriately   namespace TaxiClient { public class BootStrapper: UnityBootstrapper { protected override IModuleCatalog CreateModuleCatalog() { return new ConfigurationModuleCatalog(); } protected override DependencyObject CreateShell() { Framework.FrameworkBootStrapper.Run(Container, Application.Current.Dispatcher);   Shell shell = new Shell(); shell.ResizeMode = ResizeMode.NoResize; shell.Show();   return shell; } } } Lets take a look into  FrameworkBootStrapper to check out how to register with unity container. namespace Framework { public class FrameworkBootStrapper { public static void Run(IUnityContainer container, Dispatcher dispatcher) { UIDispatcher uiDispatcher = new UIDispatcher(dispatcher); container.RegisterInstance<IDispatcherService>(uiDispatcher);   container.RegisterType<IInjectSingleViewService, InjectSingleViewService>( new ContainerControlledLifetimeManager());   . . . } } } In the above code we are registering two components with unity container. You shall observe that we are following two different approaches, RegisterInstance and RegisterType.  With RegisterInstance we are registering an existing instance and the same instance will be returned for every request made for IDispatcherService   and with RegisterType we are requesting unity container to create an instance for us when required, i.e., when I request for an instance for IInjectSingleViewService, unity will create/return an instance of InjectSingleViewService class and with RegisterType we can configure the life time of the instance being created. With ContaienrControllerLifetimeManager, the unity container caches the instance and reuses for any subsequent requests, without recreating a new instance. Lets take a look into FareViewModel.cs and it’s constructor. The constructor takes one parameter IEventAggregator and if you try to find all references in your solution for IEventAggregator, you will not find a single location where an instance of EventAggregator is passed directly to the constructor. The compiler still finds an instance and works fine because Prism is already configured when used with Unity container to return an instance of EventAggregator when requested for IEventAggregator and in this particular case it is called constructor injection. public class FareViewModel:ObservableBase, IDataErrorInfo { ... private IEventAggregator _eventAggregator;   public FareViewModel(IEventAggregator eventAggregator) { _eventAggregator = eventAggregator; InitializePropertyNames(); InitializeModel(); PropertyChanged += OnPropertyChanged; } ... 3. Shell Shells are very similar in operation to Master Pages in asp.net or MDI in Windows Forms. And shells contain regions which display the views, you can have as many regions as you wish in a given view. You can also nest regions. i.e, one region can load a view which in itself may contain other regions. We have to create a shell at the start of the application and are doing it by overriding CreateShell method from BootStrapper From the following Shell.xaml you shall notice that we have two content controls with Region names as ‘MenuRegion’ and ‘MainRegion’.  The idea here is that you can inject any user controls into the regions dynamically, i.e., a Menu User Control for MenuRegion and based on the user action you can load appropriate view into MainRegion.    <Window x:Class="TaxiClient.Shell" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:Regions="clr-namespace:Microsoft.Practices.Prism.Regions;assembly=Microsoft.Practices.Prism" Title="Taxi" Height="370" Width="800"> <Grid Margin="2"> <ContentControl Regions:RegionManager.RegionName="MenuRegion" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" HorizontalContentAlignment="Stretch" VerticalContentAlignment="Stretch" />   <ContentControl Grid.Row="1" Regions:RegionManager.RegionName="MainRegion" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" HorizontalContentAlignment="Stretch" VerticalContentAlignment="Stretch" /> <!--<Border Grid.ColumnSpan="2" BorderThickness="2" CornerRadius="3" BorderBrush="LightBlue" />-->   </Grid> </Window> 4. Modules Prism provides the ability to build composite applications and modules play an important role in it. For example if you are building a Mortgage Loan Processor application with 3 components, i.e. customer’s credit history,  existing mortgages, new home/loan information; and consider that the customer’s credit history component involves gathering data about his/her address, background information, job details etc. The idea here using Prism modules is to separate the implementation of these 3 components into their own visual studio projects allowing to build components with no dependency on each other and independently. If we need to add another component to the application, the component can be developed by in house team or some other team in the organization by starting with a new Visual Studio project and adding to the solution at the run time with very little knowledge about the application. Prism modules are defined by implementing the IModule interface and each visual studio project to be considered as a module should implement the IModule interface.  From the BootStrapper.cs you shall observe that we are overriding the method by returning a ConfiguratingModuleCatalog which returns the modules that are registered for the application using the app.config file  and you can also add module using code. Lets take a look into configuration file.   <?xml version="1.0"?> <configuration> <configSections> <section name="modules" type="Microsoft.Practices.Prism.Modularity.ModulesConfigurationSection, Microsoft.Practices.Prism"/> </configSections> <modules> <module assemblyFile="TaxiModules.dll" moduleType="TaxiModules.ModuleInitializer, TaxiModules" moduleName="TaxiModules"/> </modules> </configuration> Here we are adding TaxiModules project to our solution and TaxiModules.ModuleInitializer implements IModule interface   5. Module Mapper With Prism modules you can dynamically add or remove modules from the regions, apart from that Prism also provides API to control adding/removing the views from a region within the same module. Taxi Information Screen: Engage the Taxi Screen: The sample application has two screens, ‘Taxi Information’ and ‘Engage the Taxi’ and they both reside in same module, TaxiModules. ‘Engage the Taxi’ is again made of two user controls, FareView on the left and TotalView on the right. We have created a Shell with two regions, MenuRegion and MainRegion with menu loaded into MenuRegion. We can create a wrapper user control called EngageTheTaxi made of FareView and TotalView and load either TaxiInfo or EngageTheTaxi into MainRegion based on the user action. Though it will work it tightly binds the user controls and for every combination of user controls, we need to create a dummy wrapper control to contain them. Instead we can apply the principles we learned so far from Shell/regions and introduce another template (LeftAndRightRegionView.xaml) made of two regions Region1 (left) and Region2 (right) and load  FareView and TotalView dynamically.  To help with loading of the views dynamically I have introduce an helper an interface, IInjectSingleViewService,  idea suggested by Mike Taulty, a must read blog for .Net developers. using System; using System.Collections.Generic; using System.ComponentModel;   namespace Framework.PresentationUtility.Navigation {   public interface IInjectSingleViewService : INotifyPropertyChanged { IEnumerable<CommandViewDefinition> Commands { get; } IEnumerable<ModuleViewDefinition> Modules { get; }   void RegisterViewForRegion(string commandName, string viewName, string regionName, Type viewType); void ClearViewFromRegion(string viewName, string regionName); void RegisterModule(string moduleName, IList<ModuleMapper> moduleMappers); } } The Interface declares three methods to work with views: RegisterViewForRegion: Registers a view with a particular region. You can register multiple views and their regions under one command.  When this particular command is invoked all the views registered under it will be loaded into their regions. ClearViewFromRegion: To unload a specific view from a region. RegisterModule: The idea is when a command is invoked you can load the UI with set of controls in their default position and based on the user interaction, you can load different contols in to different regions on the fly.  And it is supported ModuleViewDefinition and ModuleMappers as shown below. namespace Framework.PresentationUtility.Navigation { public class ModuleViewDefinition { public string ModuleName { get; set; } public IList<ModuleMapper> ModuleMappers; public ICommand Command { get; set; } }   public class ModuleMapper { public string ViewName { get; set; } public string RegionName { get; set; } public Type ViewType { get; set; } } } 6. Event Aggregator Prism event aggregator enables messaging between components as in Observable pattern, Notifier notifies the Observer which receives notification it is interested in. When it comes to Observable pattern, Observer has to unsubscribes for notifications when it no longer interested in notifications, which allows the Notifier to remove the Observer’s reference from it’s local cache. Though .Net has managed garbage collection it cannot remove inactive the instances referenced by an active instance resulting in memory leak, keeping the Observers in memory as long as Notifier stays in memory.  Developers have to be very careful to unsubscribe when necessary and it often gets overlooked, to overcome these problems Prism Event Aggregator uses weak references to cache the reference (Observer in this case)  and releases the reference (memory) once the instance goes out of scope. Using event aggregator is very simple, declare a generic type of CompositePresenationEvent by inheriting from it. using Microsoft.Practices.Prism.Events; using TaxiCommon.BAO;   namespace TaxiCommon.CompositeEvents { public class TaxiOnMoveEvent:CompositePresentationEvent<TaxiOnMove> { } }   TaxiOnMove.cs includes the properties which we want to exchange between the parties, FareView and TotalView. using System;   namespace TaxiCommon.BAO { public class TaxiOnMove { public TimeSpan MinutesAtTweleveMPH { get; set; } public double MilesAtSixMPH { get; set; } } }   Lets take a look into FareViewodel (Notifier) and how it raises the event.  Here we are raising the event by getting the event through GetEvent<..>() and publishing it with the payload private void OnAddMinutes(object obj) { TaxiOnMove payload = new TaxiOnMove(); if(MilesAtSixMPH != null) payload.MilesAtSixMPH = MilesAtSixMPH.Value; if(MinutesAtTweleveMPH != null) payload.MinutesAtTweleveMPH = new TimeSpan(0,0,MinutesAtTweleveMPH.Value,0);   _eventAggregator.GetEvent<TaxiOnMoveEvent>().Publish(payload); ResetMinutesAndMiles(); } And TotalViewModel(Observer) subscribes to notifications by getting the event through GetEvent<..>() namespace TaxiModules.ViewModels { public class TotalViewModel:ObservableBase { .... private IEventAggregator _eventAggregator;   public TotalViewModel(IEventAggregator eventAggregator) { _eventAggregator = eventAggregator; ... }   private void SubscribeToEvents() { _eventAggregator.GetEvent<TaxiStartedEvent>() .Subscribe(OnTaxiStarted, ThreadOption.UIThread,false,(filter) => true); _eventAggregator.GetEvent<TaxiOnMoveEvent>() .Subscribe(OnTaxiMove, ThreadOption.UIThread, false, (filter) => true); _eventAggregator.GetEvent<TaxiResetEvent>() .Subscribe(OnTaxiReset, ThreadOption.UIThread, false, (filter) => true); }   ... private void OnTaxiMove(TaxiOnMove taxiOnMove) { OnMoveFare fare = new OnMoveFare(taxiOnMove); Fares.Add(fare); SetTotalFare(new []{fare}); }   .... 7. MVVM through example In this section we are going to look into MVVM implementation through example.  I have all the modules declared in a single project, TaxiModules, again it is not necessary to have them into one project. Once the user logs into the application, will be greeted with the ‘Engage the Taxi’ screen which is made of two user controls, FareView.xaml and TotalView.Xaml. As you can see from the solution explorer, each of them have their own code behind files and  ViewModel classes, FareViewMode.cs, TotalViewModel.cs Lets take a look in to the FareView and how it interacts with FareViewModel using MVVM implementation. FareView.xaml acts as a view and FareViewMode.cs is it’s view model. The FareView code behind class   namespace TaxiModules.Views { /// <summary> /// Interaction logic for FareView.xaml /// </summary> public partial class FareView : UserControl { public FareView(FareViewModel viewModel) { InitializeComponent(); this.Loaded += (s, e) => { this.DataContext = viewModel; }; } } } The FareView is bound to FareViewModel through the data context  and you shall observe that DataContext is of type Object, i.e. the FareView doesn’t really know the type of ViewModel (FareViewModel). This helps separation of View and ViewModel as View and ViewModel are independent of each other, you can bind FareView to FareViewModel2 as well and the application compiles just fine. Lets take a look into FareView xaml file  <UserControl x:Class="TaxiModules.Views.FareView" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:Toolkit="clr-namespace:Microsoft.Windows.Controls;assembly=WPFToolkit" xmlns:Commands="clr-namespace:Microsoft.Practices.Prism.Commands;assembly=Microsoft.Practices.Prism"> <Grid Margin="10" > ....   <Border Style="{DynamicResource innerBorder}" Grid.Row="0" Grid.Column="0" Grid.RowSpan="11" Grid.ColumnSpan="2" Panel.ZIndex="1"/>   <Label Grid.Row="0" Content="Engage the Taxi" Style="{DynamicResource innerHeader}"/> <Label Grid.Row="1" Content="Select the State"/> <ComboBox Grid.Row="1" Grid.Column="1" ItemsSource="{Binding States}" Height="auto"> <ComboBox.ItemTemplate> <DataTemplate> <TextBlock Text="{Binding Name}"/> </DataTemplate> </ComboBox.ItemTemplate> <ComboBox.SelectedItem> <Binding Path="SelectedState" Mode="TwoWay"/> </ComboBox.SelectedItem> </ComboBox> <Label Grid.Row="2" Content="Select the Date of Entry"/> <Toolkit:DatePicker Grid.Row="2" Grid.Column="1" SelectedDate="{Binding DateOfEntry, ValidatesOnDataErrors=true}" /> <Label Grid.Row="3" Content="Enter time 24hr format"/> <TextBox Grid.Row="3" Grid.Column="1" Text="{Binding TimeOfEntry, TargetNullValue=''}"/> <Button Grid.Row="4" Grid.Column="1" Content="Start the Meter" Commands:Click.Command="{Binding StartMeterCommand}" />   <Label Grid.Row="5" Content="Run the Taxi" Style="{DynamicResource innerHeader}"/> <Label Grid.Row="6" Content="Number of Miles &lt;@6mph"/> <TextBox Grid.Row="6" Grid.Column="1" Text="{Binding MilesAtSixMPH, TargetNullValue='', ValidatesOnDataErrors=true}"/> <Label Grid.Row="7" Content="Number of Minutes @12mph"/> <TextBox Grid.Row="7" Grid.Column="1" Text="{Binding MinutesAtTweleveMPH, TargetNullValue=''}"/> <Button Grid.Row="8" Grid.Column="1" Content="Add Minutes and Miles " Commands:Click.Command="{Binding AddMinutesCommand}"/> <Label Grid.Row="9" Content="Other Operations" Style="{DynamicResource innerHeader}"/> <Button Grid.Row="10" Grid.Column="1" Content="Reset the Meter" Commands:Click.Command="{Binding ResetCommand}"/>   </Grid> </UserControl> The highlighted code from the above code shows data binding, for example ComboBox which displays list of states has it’s ItemsSource bound to States property, with DataTemplate bound to Name and SelectedItem  to SelectedState. You might be wondering what are all these properties and how it is able to bind to them.  The answer lies in data context, i.e., when you bound a control, WPF looks for data context on the root object (Grid in this case) and if it can’t find data context it will look into root’s root, i.e. FareView UserControl and it is bound to FareViewModel.  Each of those properties have be declared on the ViewModel for the View to bind correctly. To put simply, View is bound to ViewModel through data context of type object and every control that is bound on the View actually binds to the public property on the ViewModel. Lets look into the ViewModel code (the following code is not an exact copy of FareViewMode.cs, pasted relevant code for this section)   namespace TaxiModules.ViewModels { public class FareViewModel:ObservableBase, IDataErrorInfo { public List<USState> States { get { return USStates.StateList; } }   public USState SelectedState { get { return _selectedState; } set { _selectedState = value; RaisePropertyChanged(_selectedStatePropertyName); } }   public DateTime? DateOfEntry { get { return _dateOfEntry; } set { _dateOfEntry = value; RaisePropertyChanged(_dateOfEntryPropertyName); } }   public TimeSpan? TimeOfEntry { get { return _timeOfEntry; } set { _timeOfEntry = value; RaisePropertyChanged(_timeOfEntryPropertyName); } }   public double? MilesAtSixMPH { get { return _milesAtSixMPH; } set { _milesAtSixMPH = value; RaisePropertyChanged(_distanceAtSixMPHPropertyName); } }   public int? MinutesAtTweleveMPH { get { return _minutesAtTweleveMPH; } set { _minutesAtTweleveMPH = value; RaisePropertyChanged(_minutesAtTweleveMPHPropertyName); } }   public ICommand StartMeterCommand { get { if(_startMeterCommand == null) { _startMeterCommand = new DelegateCommand<object>(OnStartMeter, CanStartMeter); } return _startMeterCommand; } }   public ICommand AddMinutesCommand { get { if(_addMinutesCommand == null) { _addMinutesCommand = new DelegateCommand<object>(OnAddMinutes, CanAddMinutes); } return _addMinutesCommand; } }   public ICommand ResetCommand { get { if(_resetCommand == null) { _resetCommand = new DelegateCommand<object>(OnResetCommand); } return _resetCommand; } }   } private void OnStartMeter(object obj) { _eventAggregator.GetEvent<TaxiStartedEvent>().Publish( new TaxiStarted() { EngagedOn = DateOfEntry.Value.Date + TimeOfEntry.Value, EngagedState = SelectedState.Value });   _isMeterStarted = true; OnPropertyChanged(this,null); } And views communicate user actions like button clicks, tree view item selections, etc using commands. When user clicks on ‘Start the Meter’ button it invokes the method StartMeterCommand, which calls the method OnStartMeter which publishes the event to TotalViewModel using event aggregator  and TaxiStartedEvent. namespace TaxiModules.ViewModels { public class TotalViewModel:ObservableBase { ... private IEventAggregator _eventAggregator;   public TotalViewModel(IEventAggregator eventAggregator) { _eventAggregator = eventAggregator;   InitializePropertyNames(); InitializeModel(); SubscribeToEvents(); }   public decimal? TotalFare { get { return _totalFare; } set { _totalFare = value; RaisePropertyChanged(_totalFarePropertyName); } } .... private void SubscribeToEvents() { _eventAggregator.GetEvent<TaxiStartedEvent>().Subscribe(OnTaxiStarted, ThreadOption.UIThread,false,(filter) => true); _eventAggregator.GetEvent<TaxiOnMoveEvent>().Subscribe(OnTaxiMove, ThreadOption.UIThread, false, (filter) => true); _eventAggregator.GetEvent<TaxiResetEvent>().Subscribe(OnTaxiReset, ThreadOption.UIThread, false, (filter) => true); }   private void OnTaxiStarted(TaxiStarted taxiStarted) { Fares.Add(new EntryFare()); Fares.Add(new StateTaxFare(taxiStarted)); Fares.Add(new NightSurchargeFare(taxiStarted)); Fares.Add(new PeakHourWeekdayFare(taxiStarted));   SetTotalFare(Fares); }   private void SetTotalFare(IEnumerable<IFare> fares) { TotalFare = (_totalFare ?? 0) + TaxiFareHelper.GetTotalFare(fares); } ....   } }   TotalViewModel subscribes to events, TaxiStartedEvent and rest. When TaxiStartedEvent gets invoked it calls the OnTaxiStarted method which sets the total fare which includes entry fee, state tax, nightly surcharge, peak hour weekday fare.   Note that TotalViewModel derives from ObservableBase which implements the method RaisePropertyChanged which we are invoking in Set of TotalFare property, i.e, once we update the TotalFare property it raises an the event that  allows the TotalFare text box to fetch the new value through the data context. ViewModel is communicating with View through data context and it has no knowledge about View, helping in loose coupling of ViewModel and View.   I have attached the source code (.Net 4.0, Prism 4.0, VS 2010) , download and play with it and don’t forget to leave your comments.  

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• Using the West Wind Web Toolkit to set up AJAX and REST Services

  - by Rick Strahl

  I frequently get questions about which option to use for creating AJAX and REST backends for ASP.NET applications. There are many solutions out there to do this actually, but when I have a choice - not surprisingly - I fall back to my own tools in the West Wind West Wind Web Toolkit. I've talked a bunch about the 'in-the-box' solutions in the past so for a change in this post I'll talk about the tools that I use in my own and customer applications to handle AJAX and REST based access to service resources using the West Wind West Wind Web Toolkit. Let me preface this by saying that I like things to be easy. Yes flexible is very important as well but not at the expense of over-complexity. The goal I've had with my tools is make it drop dead easy, with good performance while providing the core features that I'm after, which are: Easy AJAX/JSON Callbacks Ability to return any kind of non JSON content (string, stream, byte[], images) Ability to work with both XML and JSON interchangeably for input/output Access endpoints via POST data, RPC JSON calls, GET QueryString values or Routing interface Easy to use generic JavaScript client to make RPC calls (same syntax, just what you need) Ability to create clean URLS with Routing Ability to use standard ASP.NET HTTP Stack for HTTP semantics It's all about options! In this post I'll demonstrate most of these features (except XML) in a few simple and short samples which you can download. So let's take a look and see how you can build an AJAX callback solution with the West Wind Web Toolkit. Installing the Toolkit Assemblies The easiest and leanest way of using the Toolkit in your Web project is to grab it via NuGet: West Wind Web and AJAX Utilities (Westwind.Web) and drop it into the project by right clicking in your Project and choosing Manage NuGet Packages from anywhere in the Project.   When done you end up with your project looking like this: What just happened? Nuget added two assemblies - Westwind.Web and Westwind.Utilities and the client ww.jquery.js library. It also added a couple of references into web.config: The default namespaces so they can be accessed in pages/views and a ScriptCompressionModule that the toolkit optionally uses to compress script resources served from within the assembly (namely ww.jquery.js and optionally jquery.js). Creating a new Service The West Wind Web Toolkit supports several ways of creating and accessing AJAX services, but for this post I'll stick to the lower level approach that works from any plain HTML page or of course MVC, WebForms, WebPages. There's also a WebForms specific control that makes this even easier but I'll leave that for another post. So, to create a new standalone AJAX/REST service we can create a new HttpHandler in the new project either as a pure class based handler or as a generic .ASHX handler. Both work equally well, but generic handlers don't require any web.config configuration so I'll use that here. In the root of the project add a Generic Handler. I'm going to call this one StockService.ashx. Once the handler has been created, edit the code and remove all of the handler body code. Then change the base class to CallbackHandler and add methods that have a [CallbackMethod] attribute. Here's the modified base handler implementation now looks like with an added HelloWorld method: using System; using Westwind.Web; namespace WestWindWebAjax { /// <summary> /// Handler implements CallbackHandler to provide REST/AJAX services /// </summary> public class SampleService : CallbackHandler { [CallbackMethod] public string HelloWorld(string name) { return "Hello " + name + ". Time is: " + DateTime.Now.ToString(); } } } Notice that the class inherits from CallbackHandler and that the HelloWorld service method is marked up with [CallbackMethod]. We're done here. Services Urlbased Syntax Once you compile, the 'service' is live can respond to requests. All CallbackHandlers support input in GET and POST formats, and can return results as JSON or XML. To check our fancy HelloWorld method we can now access the service like this: http://localhost/WestWindWebAjax/StockService.ashx?Method=HelloWorld&name=Rick which produces a default JSON response - in this case a string (wrapped in quotes as it's JSON): (note by default JSON will be downloaded by most browsers not displayed - various options are available to view JSON right in the browser) If I want to return the same data as XML I can tack on a &format=xml at the end of the querystring which produces: <string>Hello Rick. Time is: 11/1/2011 12:11:13 PM</string> Cleaner URLs with Routing Syntax If you want cleaner URLs for each operation you can also configure custom routes on a per URL basis similar to the way that WCF REST does. To do this you need to add a new RouteHandler to your application's startup code in global.asax.cs one for each CallbackHandler based service you create: protected void Application_Start(object sender, EventArgs e) { CallbackHandlerRouteHandler.RegisterRoutes<StockService>(RouteTable.Routes); } With this code in place you can now add RouteUrl properties to any of your service methods. For the HelloWorld method that doesn't make a ton of sense but here is what a routed clean URL might look like in definition: [CallbackMethod(RouteUrl="stocks/HelloWorld/{name}")] public string HelloWorld(string name) { return "Hello " + name + ". Time is: " + DateTime.Now.ToString(); } The same URL I previously used now becomes a bit shorter and more readable with: http://localhost/WestWindWebAjax/HelloWorld/Rick It's an easy way to create cleaner URLs and still get the same functionality. Calling the Service with $.getJSON() Since the result produced is JSON you can now easily consume this data using jQuery's getJSON method. First we need a couple of scripts - jquery.js and ww.jquery.js in the page: <!DOCTYPE html> <html> <head> <link href="Css/Westwind.css" rel="stylesheet" type="text/css" /> <script src="scripts/jquery.min.js" type="text/javascript"></script> <script src="scripts/ww.jquery.min.js" type="text/javascript"></script> </head> <body> Next let's add a small HelloWorld example form (what else) that has a single textbox to type a name, a button and a div tag to receive the result: <fieldset> <legend>Hello World</legend> Please enter a name: <input type="text" name="txtHello" id="txtHello" value="" /> <input type="button" id="btnSayHello" value="Say Hello (POST)" /> <input type="button" id="btnSayHelloGet" value="Say Hello (GET)" /> <div id="divHelloMessage" class="errordisplay" style="display:none;width: 450px;" > </div> </fieldset> Then to call the HelloWorld method a little jQuery is used to hook the document startup and the button click followed by the $.getJSON call to retrieve the data from the server. <script type="text/javascript"> $(document).ready(function () { $("#btnSayHelloGet").click(function () { $.getJSON("SampleService.ashx", { Method: "HelloWorld", name: $("#txtHello").val() }, function (result) { $("#divHelloMessage") .text(result) .fadeIn(1000); }); });</script> .getJSON() expects a full URL to the endpoint of our service, which is the ASHX file. We can either provide a full URL (SampleService.ashx?Method=HelloWorld&name=Rick) or we can just provide the base URL and an object that encodes the query string parameters for us using an object map that has a property that matches each parameter for the server method. We can also use the clean URL routing syntax, but using the object parameter encoding actually is safer as the parameters will get properly encoded by jQuery. The result returned is whatever the result on the server method is - in this case a string. The string is applied to the divHelloMessage element and we're done. Obviously this is a trivial example, but it demonstrates the basics of getting a JSON response back to the browser. AJAX Post Syntax - using ajaxCallMethod() The previous example allows you basic control over the data that you send to the server via querystring parameters. This works OK for simple values like short strings, numbers and boolean values, but doesn't really work if you need to pass something more complex like an object or an array back up to the server. To handle traditional RPC type messaging where the idea is to map server side functions and results to a client side invokation, POST operations can be used. The easiest way to use this functionality is to use ww.jquery.js and the ajaxCallMethod() function. ww.jquery wraps jQuery's AJAX functions and knows implicitly how to call a CallbackServer method with parameters and parse the result. Let's look at another simple example that posts a simple value but returns something more interesting. Let's start with the service method: [CallbackMethod(RouteUrl="stocks/{symbol}")] public StockQuote GetStockQuote(string symbol) { Response.Cache.SetExpires(DateTime.UtcNow.Add(new TimeSpan(0, 2, 0))); StockServer server = new StockServer(); var quote = server.GetStockQuote(symbol); if (quote == null) throw new ApplicationException("Invalid Symbol passed."); return quote; } This sample utilizes a small StockServer helper class (included in the sample) that downloads a stock quote from Yahoo's financial site via plain HTTP GET requests and formats it into a StockQuote object. Lets create a small HTML block that lets us query for the quote and display it: <fieldset> <legend>Single Stock Quote</legend> Please enter a stock symbol: <input type="text" name="txtSymbol" id="txtSymbol" value="msft" /> <input type="button" id="btnStockQuote" value="Get Quote" /> <div id="divStockDisplay" class="errordisplay" style="display:none; width: 450px;"> <div class="label-left">Company:</div> <div id="stockCompany"></div> <div class="label-left">Last Price:</div> <div id="stockLastPrice"></div> <div class="label-left">Quote Time:</div> <div id="stockQuoteTime"></div> </div> </fieldset> The final result looks something like this:   Let's hook up the button handler to fire the request and fill in the data as shown: $("#btnStockQuote").click(function () { ajaxCallMethod("SampleService.ashx", "GetStockQuote", [$("#txtSymbol").val()], function (quote) { $("#divStockDisplay").show().fadeIn(1000); $("#stockCompany").text(quote.Company + " (" + quote.Symbol + ")"); $("#stockLastPrice").text(quote.LastPrice); $("#stockQuoteTime").text(quote.LastQuoteTime.formatDate("MMM dd, HH:mm EST")); }, onPageError); }); So we point at SampleService.ashx and the GetStockQuote method, passing a single parameter of the input symbol value. Then there are two handlers for success and failure callbacks.  The success handler is the interesting part - it receives the stock quote as a result and assigns its values to various 'holes' in the stock display elements. The data that comes back over the wire is JSON and it looks like this: { "Symbol":"MSFT", "Company":"Microsoft Corpora", "OpenPrice":26.11, "LastPrice":26.01, "NetChange":0.02, "LastQuoteTime":"2011-11-03T02:00:00Z", "LastQuoteTimeString":"Nov. 11, 2011 4:20pm" } which is an object representation of the data. JavaScript can evaluate this JSON string back into an object easily and that's the reslut that gets passed to the success function. The quote data is then applied to existing page content by manually selecting items and applying them. There are other ways to do this more elegantly like using templates, but here we're only interested in seeing how the data is returned. The data in the object is typed - LastPrice is a number and QuoteTime is a date. Note about the date value: JavaScript doesn't have a date literal although the JSON embedded ISO string format used above  ("2011-11-03T02:00:00Z") is becoming fairly standard for JSON serializers. However, JSON parsers don't deserialize dates by default and return them by string. This is why the StockQuote actually returns a string value of LastQuoteTimeString for the same date. ajaxMethodCallback always converts dates properly into 'real' dates and the example above uses the real date value along with a .formatDate() data extension (also in ww.jquery.js) to display the raw date properly. Errors and Exceptions So what happens if your code fails? For example if I pass an invalid stock symbol to the GetStockQuote() method you notice that the code does this: if (quote == null) throw new ApplicationException("Invalid Symbol passed."); CallbackHandler automatically pushes the exception message back to the client so it's easy to pick up the error message. Regardless of what kind of error occurs: Server side, client side, protocol errors - any error will fire the failure handler with an error object parameter. The error is returned to the client via a JSON response in the error callback. In the previous examples I called onPageError which is a generic routine in ww.jquery that displays a status message on the bottom of the screen. But of course you can also take over the error handling yourself: $("#btnStockQuote").click(function () { ajaxCallMethod("SampleService.ashx", "GetStockQuote", [$("#txtSymbol").val()], function (quote) { $("#divStockDisplay").fadeIn(1000); $("#stockCompany").text(quote.Company + " (" + quote.Symbol + ")"); $("#stockLastPrice").text(quote.LastPrice); $("#stockQuoteTime").text(quote.LastQuoteTime.formatDate("MMM dd, hh:mmt")); }, function (error, xhr) { $("#divErrorDisplay").text(error.message).fadeIn(1000); }); }); The error object has a isCallbackError, message and  stackTrace properties, the latter of which is only populated when running in Debug mode, and this object is returned for all errors: Client side, transport and server side errors. Regardless of which type of error you get the same object passed (as well as the XHR instance optionally) which makes for a consistent error retrieval mechanism. Specifying HttpVerbs You can also specify HTTP Verbs that are allowed using the AllowedHttpVerbs option on the CallbackMethod attribute: [CallbackMethod(AllowedHttpVerbs=HttpVerbs.GET | HttpVerbs.POST)] public string HelloWorld(string name) { … } If you're building REST style API's this might be useful to force certain request semantics onto the client calling. For the above if call with a non-allowed HttpVerb the request returns a 405 error response along with a JSON (or XML) error object result. The default behavior is to allow all verbs access (HttpVerbs.All). Passing in object Parameters Up to now the parameters I passed were very simple. But what if you need to send something more complex like an object or an array? Let's look at another example now that passes an object from the client to the server. Keeping with the Stock theme here lets add a method called BuyOrder that lets us buy some shares for a stock. Consider the following service method that receives an StockBuyOrder object as a parameter: [CallbackMethod] public string BuyStock(StockBuyOrder buyOrder) { var server = new StockServer(); var quote = server.GetStockQuote(buyOrder.Symbol); if (quote == null) throw new ApplicationException("Invalid or missing stock symbol."); return string.Format("You're buying {0} shares of {1} ({2}) stock at {3} for a total of {4} on {5}.", buyOrder.Quantity, quote.Company, quote.Symbol, quote.LastPrice.ToString("c"), (quote.LastPrice * buyOrder.Quantity).ToString("c"), buyOrder.BuyOn.ToString("MMM d")); } public class StockBuyOrder { public string Symbol { get; set; } public int Quantity { get; set; } public DateTime BuyOn { get; set; } public StockBuyOrder() { BuyOn = DateTime.Now; } } This is a contrived do-nothing example that simply echoes back what was passed in, but it demonstrates how you can pass complex data to a callback method. On the client side we now have a very simple form that captures the three values on a form: <fieldset> <legend>Post a Stock Buy Order</legend> Enter a symbol: <input type="text" name="txtBuySymbol" id="txtBuySymbol" value="GLD" />&nbsp;&nbsp; Qty: <input type="text" name="txtBuyQty" id="txtBuyQty" value="10" style="width: 50px" />&nbsp;&nbsp; Buy on: <input type="text" name="txtBuyOn" id="txtBuyOn" value="<%= DateTime.Now.ToString("d") %>" style="width: 70px;" /> <input type="button" id="btnBuyStock" value="Buy Stock" /> <div id="divStockBuyMessage" class="errordisplay" style="display:none"></div> </fieldset> The completed form and demo then looks something like this:   The client side code that picks up the input values and assigns them to object properties and sends the AJAX request looks like this: $("#btnBuyStock").click(function () { // create an object map that matches StockBuyOrder signature var buyOrder = { Symbol: $("#txtBuySymbol").val(), Quantity: $("#txtBuyQty").val() * 1, // number Entered: new Date() } ajaxCallMethod("SampleService.ashx", "BuyStock", [buyOrder], function (result) { $("#divStockBuyMessage").text(result).fadeIn(1000); }, onPageError); }); The code creates an object and attaches the properties that match the server side object passed to the BuyStock method. Each property that you want to update needs to be included and the type must match (ie. string, number, date in this case). Any missing properties will not be set but also not cause any errors. Pass POST data instead of Objects In the last example I collected a bunch of values from form variables and stuffed them into object variables in JavaScript code. While that works, often times this isn't really helping - I end up converting my types on the client and then doing another conversion on the server. If lots of input controls are on a page and you just want to pick up the values on the server via plain POST variables - that can be done too - and it makes sense especially if you're creating and filling the client side object only to push data to the server. Let's add another method to the server that once again lets us buy a stock. But this time let's not accept a parameter but rather send POST data to the server. Here's the server method receiving POST data: [CallbackMethod] public string BuyStockPost() { StockBuyOrder buyOrder = new StockBuyOrder(); buyOrder.Symbol = Request.Form["txtBuySymbol"]; ; int qty; int.TryParse(Request.Form["txtBuyQuantity"], out qty); buyOrder.Quantity = qty; DateTime time; DateTime.TryParse(Request.Form["txtBuyBuyOn"], out time); buyOrder.BuyOn = time; // Or easier way yet //FormVariableBinder.Unbind(buyOrder,null,"txtBuy"); var server = new StockServer(); var quote = server.GetStockQuote(buyOrder.Symbol); if (quote == null) throw new ApplicationException("Invalid or missing stock symbol."); return string.Format("You're buying {0} shares of {1} ({2}) stock at {3} for a total of {4} on {5}.", buyOrder.Quantity, quote.Company, quote.Symbol, quote.LastPrice.ToString("c"), (quote.LastPrice * buyOrder.Quantity).ToString("c"), buyOrder.BuyOn.ToString("MMM d")); } Clearly we've made this server method take more code than it did with the object parameter. We've basically moved the parameter assignment logic from the client to the server. As a result the client code to call this method is now a bit shorter since there's no client side shuffling of values from the controls to an object. $("#btnBuyStockPost").click(function () { ajaxCallMethod("SampleService.ashx", "BuyStockPost", [], // Note: No parameters - function (result) { $("#divStockBuyMessage").text(result).fadeIn(1000); }, onPageError, // Force all page Form Variables to be posted { postbackMode: "Post" }); }); The client simply calls the BuyStockQuote method and pushes all the form variables from the page up to the server which parses them instead. The feature that makes this work is one of the options you can pass to the ajaxCallMethod() function: { postbackMode: "Post" }); which directs the function to include form variable POST data when making the service call. Other options include PostNoViewState (for WebForms to strip out WebForms crap vars), PostParametersOnly (default), None. If you pass parameters those are always posted to the server except when None is set. The above code can be simplified a bit by using the FormVariableBinder helper, which can unbind form variables directly into an object: FormVariableBinder.Unbind(buyOrder,null,"txtBuy"); which replaces the manual Request.Form[] reading code. It receives the object to unbind into, a string of properties to skip, and an optional prefix which is stripped off form variables to match property names. The component is similar to the MVC model binder but it's independent of MVC. Returning non-JSON Data CallbackHandler also supports returning non-JSON/XML data via special return types. You can return raw non-JSON encoded strings like this: [CallbackMethod(ReturnAsRawString=true,ContentType="text/plain")] public string HelloWorldNoJSON(string name) { return "Hello " + name + ". Time is: " + DateTime.Now.ToString(); } Calling this method results in just a plain string - no JSON encoding with quotes around the result. This can be useful if your server handling code needs to return a string or HTML result that doesn't fit well for a page or other UI component. Any string output can be returned. You can also return binary data. Stream, byte[] and Bitmap/Image results are automatically streamed back to the client. Notice that you should set the ContentType of the request either on the CallbackMethod attribute or using Response.ContentType. This ensures the Web Server knows how to display your binary response. Using a stream response makes it possible to return any of data. Streamed data can be pretty handy to return bitmap data from a method. The following is a method that returns a stock history graph for a particular stock over a provided number of years: [CallbackMethod(ContentType="image/png",RouteUrl="stocks/history/graph/{symbol}/{years}")] public Stream GetStockHistoryGraph(string symbol, int years = 2,int width = 500, int height=350) { if (width == 0) width = 500; if (height == 0) height = 350; StockServer server = new StockServer(); return server.GetStockHistoryGraph(symbol,"Stock History for " + symbol,width,height,years); } I can now hook this up into the JavaScript code when I get a stock quote. At the end of the process I can assign the URL to the service that returns the image into the src property and so force the image to display. Here's the changed code: $("#btnStockQuote").click(function () { var symbol = $("#txtSymbol").val(); ajaxCallMethod("SampleService.ashx", "GetStockQuote", [symbol], function (quote) { $("#divStockDisplay").fadeIn(1000); $("#stockCompany").text(quote.Company + " (" + quote.Symbol + ")"); $("#stockLastPrice").text(quote.LastPrice); $("#stockQuoteTime").text(quote.LastQuoteTime.formatDate("MMM dd, hh:mmt")); // display a stock chart $("#imgStockHistory").attr("src", "stocks/history/graph/" + symbol + "/2"); },onPageError); }); The resulting output then looks like this: The charting code uses the new ASP.NET 4.0 Chart components via code to display a bar chart of the 2 year stock data as part of the StockServer class which you can find in the sample download. The ability to return arbitrary data from a service is useful as you can see - in this case the chart is clearly associated with the service and it's nice that the graph generation can happen off a handler rather than through a page. Images are common resources, but output can also be PDF reports, zip files for downloads etc. which is becoming increasingly more common to be returned from REST endpoints and other applications. Why reinvent? Obviously the examples I've shown here are pretty basic in terms of functionality. But I hope they demonstrate the core features of AJAX callbacks that you need to work through in most applications which is simple: return data, send back data and potentially retrieve data in various formats. While there are other solutions when it comes down to making AJAX callbacks and servicing REST like requests, I like the flexibility my home grown solution provides. Simply put it's still the easiest solution that I've found that addresses my common use cases: AJAX JSON RPC style callbacks Url based access XML and JSON Output from single method endpoint XML and JSON POST support, querystring input, routing parameter mapping UrlEncoded POST data support on callbacks Ability to return stream/raw string data Essentially ability to return ANYTHING from Service and pass anything All these features are available in various solutions but not together in one place. I've been using this code base for over 4 years now in a number of projects both for myself and commercial work and it's served me extremely well. Besides the AJAX functionality CallbackHandler provides, it's also an easy way to create any kind of output endpoint I need to create. Need to create a few simple routines that spit back some data, but don't want to create a Page or View or full blown handler for it? Create a CallbackHandler and add a method or multiple methods and you have your generic endpoints.  It's a quick and easy way to add small code pieces that are pretty efficient as they're running through a pretty small handler implementation. I can have this up and running in a couple of minutes literally without any setup and returning just about any kind of data. Resources Download the Sample NuGet: Westwind Web and AJAX Utilities (Westwind.Web) ajaxCallMethod() Documentation Using the AjaxMethodCallback WebForms Control West Wind Web Toolkit Home Page West Wind Web Toolkit Source Code © Rick Strahl, West Wind Technologies, 2005-2011Posted in ASP.NET  jQuery  AJAX   Tweet (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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• How LINQ to Object statements work

  - by rajbk

  This post goes into detail as to now LINQ statements work when querying a collection of objects. This topic assumes you have an understanding of how generics, delegates, implicitly typed variables, lambda expressions, object/collection initializers, extension methods and the yield statement work. I would also recommend you read my previous two posts: Using Delegates in C# Part 1 Using Delegates in C# Part 2 We will start by writing some methods to filter a collection of data. Assume we have an Employee class like so: 1: public class Employee { 2: public int ID { get; set;} 3: public string FirstName { get; set;} 4: public string LastName {get; set;} 5: public string Country { get; set; } 6: } and a collection of employees like so: 1: var employees = new List<Employee> { 2: new Employee { ID = 1, FirstName = "John", LastName = "Wright", Country = "USA" }, 3: new Employee { ID = 2, FirstName = "Jim", LastName = "Ashlock", Country = "UK" }, 4: new Employee { ID = 3, FirstName = "Jane", LastName = "Jackson", Country = "CHE" }, 5: new Employee { ID = 4, FirstName = "Jill", LastName = "Anderson", Country = "AUS" }, 6: }; Filtering We wish to  find all employees that have an even ID. We could start off by writing a method that takes in a list of employees and returns a filtered list of employees with an even ID. 1: static List<Employee> GetEmployeesWithEvenID(List<Employee> employees) { 2: var filteredEmployees = new List<Employee>(); 3: foreach (Employee emp in employees) { 4: if (emp.ID % 2 == 0) { 5: filteredEmployees.Add(emp); 6: } 7: } 8: return filteredEmployees; 9: } The method can be rewritten to return an IEnumerable<Employee> using the yield return keyword. 1: static IEnumerable<Employee> GetEmployeesWithEvenID(IEnumerable<Employee> employees) { 2: foreach (Employee emp in employees) { 3: if (emp.ID % 2 == 0) { 4: yield return emp; 5: } 6: } 7: } We put these together in a console application. 1: using System; 2: using System.Collections.Generic; 3: //No System.Linq 4:  5: public class Program 6: { 7: [STAThread] 8: static void Main(string[] args) 9: { 10: var employees = new List<Employee> { 11: new Employee { ID = 1, FirstName = "John", LastName = "Wright", Country = "USA" }, 12: new Employee { ID = 2, FirstName = "Jim", LastName = "Ashlock", Country = "UK" }, 13: new Employee { ID = 3, FirstName = "Jane", LastName = "Jackson", Country = "CHE" }, 14: new Employee { ID = 4, FirstName = "Jill", LastName = "Anderson", Country = "AUS" }, 15: }; 16: var filteredEmployees = GetEmployeesWithEvenID(employees); 17:  18: foreach (Employee emp in filteredEmployees) { 19: Console.WriteLine("ID {0} First_Name {1} Last_Name {2} Country {3}", 20: emp.ID, emp.FirstName, emp.LastName, emp.Country); 21: } 22:  23: Console.ReadLine(); 24: } 25: 26: static IEnumerable<Employee> GetEmployeesWithEvenID(IEnumerable<Employee> employees) { 27: foreach (Employee emp in employees) { 28: if (emp.ID % 2 == 0) { 29: yield return emp; 30: } 31: } 32: } 33: } 34:  35: public class Employee { 36: public int ID { get; set;} 37: public string FirstName { get; set;} 38: public string LastName {get; set;} 39: public string Country { get; set; } 40: } Output: ID 2 First_Name Jim Last_Name Ashlock Country UK ID 4 First_Name Jill Last_Name Anderson Country AUS Our filtering method is too specific. Let us change it so that it is capable of doing different types of filtering and lets give our method the name Where ;-) We will add another parameter to our Where method. This additional parameter will be a delegate with the following declaration. public delegate bool Filter(Employee emp); The idea is that the delegate parameter in our Where method will point to a method that contains the logic to do our filtering thereby freeing our Where method from any dependency. The method is shown below: 1: static IEnumerable<Employee> Where(IEnumerable<Employee> employees, Filter filter) { 2: foreach (Employee emp in employees) { 3: if (filter(emp)) { 4: yield return emp; 5: } 6: } 7: } Making the change to our app, we create a new instance of the Filter delegate on line 14 with a target set to the method EmployeeHasEvenId. Running the code will produce the same output. 1: public delegate bool Filter(Employee emp); 2:  3: public class Program 4: { 5: [STAThread] 6: static void Main(string[] args) 7: { 8: var employees = new List<Employee> { 9: new Employee { ID = 1, FirstName = "John", LastName = "Wright", Country = "USA" }, 10: new Employee { ID = 2, FirstName = "Jim", LastName = "Ashlock", Country = "UK" }, 11: new Employee { ID = 3, FirstName = "Jane", LastName = "Jackson", Country = "CHE" }, 12: new Employee { ID = 4, FirstName = "Jill", LastName = "Anderson", Country = "AUS" } 13: }; 14: var filterDelegate = new Filter(EmployeeHasEvenId); 15: var filteredEmployees = Where(employees, filterDelegate); 16:  17: foreach (Employee emp in filteredEmployees) { 18: Console.WriteLine("ID {0} First_Name {1} Last_Name {2} Country {3}", 19: emp.ID, emp.FirstName, emp.LastName, emp.Country); 20: } 21: Console.ReadLine(); 22: } 23: 24: static bool EmployeeHasEvenId(Employee emp) { 25: return emp.ID % 2 == 0; 26: } 27: 28: static IEnumerable<Employee> Where(IEnumerable<Employee> employees, Filter filter) { 29: foreach (Employee emp in employees) { 30: if (filter(emp)) { 31: yield return emp; 32: } 33: } 34: } 35: } 36:  37: public class Employee { 38: public int ID { get; set;} 39: public string FirstName { get; set;} 40: public string LastName {get; set;} 41: public string Country { get; set; } 42: } Lets use lambda expressions to inline the contents of the EmployeeHasEvenId method in place of the method. The next code snippet shows this change (see line 15).  For brevity, the Employee class declaration has been skipped. 1: public delegate bool Filter(Employee emp); 2:  3: public class Program 4: { 5: [STAThread] 6: static void Main(string[] args) 7: { 8: var employees = new List<Employee> { 9: new Employee { ID = 1, FirstName = "John", LastName = "Wright", Country = "USA" }, 10: new Employee { ID = 2, FirstName = "Jim", LastName = "Ashlock", Country = "UK" }, 11: new Employee { ID = 3, FirstName = "Jane", LastName = "Jackson", Country = "CHE" }, 12: new Employee { ID = 4, FirstName = "Jill", LastName = "Anderson", Country = "AUS" } 13: }; 14: var filterDelegate = new Filter(EmployeeHasEvenId); 15: var filteredEmployees = Where(employees, emp => emp.ID % 2 == 0); 16:  17: foreach (Employee emp in filteredEmployees) { 18: Console.WriteLine("ID {0} First_Name {1} Last_Name {2} Country {3}", 19: emp.ID, emp.FirstName, emp.LastName, emp.Country); 20: } 21: Console.ReadLine(); 22: } 23: 24: static bool EmployeeHasEvenId(Employee emp) { 25: return emp.ID % 2 == 0; 26: } 27: 28: static IEnumerable<Employee> Where(IEnumerable<Employee> employees, Filter filter) { 29: foreach (Employee emp in employees) { 30: if (filter(emp)) { 31: yield return emp; 32: } 33: } 34: } 35: } 36:  The output displays the same two employees.  Our Where method is too restricted since it works with a collection of Employees only. Lets change it so that it works with any IEnumerable<T>. In addition, you may recall from my previous post,  that .NET 3.5 comes with a lot of predefined delegates including public delegate TResult Func<T, TResult>(T arg); We will get rid of our Filter delegate and use the one above instead. We apply these two changes to our code. 1: public class Program 2: { 3: [STAThread] 4: static void Main(string[] args) 5: { 6: var employees = new List<Employee> { 7: new Employee { ID = 1, FirstName = "John", LastName = "Wright", Country = "USA" }, 8: new Employee { ID = 2, FirstName = "Jim", LastName = "Ashlock", Country = "UK" }, 9: new Employee { ID = 3, FirstName = "Jane", LastName = "Jackson", Country = "CHE" }, 10: new Employee { ID = 4, FirstName = "Jill", LastName = "Anderson", Country = "AUS" } 11: }; 12:  13: var filteredEmployees = Where(employees, emp => emp.ID % 2 == 0); 14:  15: foreach (Employee emp in filteredEmployees) { 16: Console.WriteLine("ID {0} First_Name {1} Last_Name {2} Country {3}", 17: emp.ID, emp.FirstName, emp.LastName, emp.Country); 18: } 19: Console.ReadLine(); 20: } 21: 22: static IEnumerable<T> Where<T>(IEnumerable<T> source, Func<T, bool> filter) { 23: foreach (var x in source) { 24: if (filter(x)) { 25: yield return x; 26: } 27: } 28: } 29: } We have successfully implemented a way to filter any IEnumerable<T> based on a  filter criteria. Projection Now lets enumerate on the items in the IEnumerable<Employee> we got from the Where method and copy them into a new IEnumerable<EmployeeFormatted>. The EmployeeFormatted class will only have a FullName and ID property. 1: public class EmployeeFormatted { 2: public int ID { get; set; } 3: public string FullName {get; set;} 4: } We could “project” our existing IEnumerable<Employee> into a new collection of IEnumerable<EmployeeFormatted> with the help of a new method. We will call this method Select ;-) 1: static IEnumerable<EmployeeFormatted> Select(IEnumerable<Employee> employees) { 2: foreach (var emp in employees) { 3: yield return new EmployeeFormatted { 4: ID = emp.ID, 5: FullName = emp.LastName + ", " + emp.FirstName 6: }; 7: } 8: } The changes are applied to our app. 1: public class Program 2: { 3: [STAThread] 4: static void Main(string[] args) 5: { 6: var employees = new List<Employee> { 7: new Employee { ID = 1, FirstName = "John", LastName = "Wright", Country = "USA" }, 8: new Employee { ID = 2, FirstName = "Jim", LastName = "Ashlock", Country = "UK" }, 9: new Employee { ID = 3, FirstName = "Jane", LastName = "Jackson", Country = "CHE" }, 10: new Employee { ID = 4, FirstName = "Jill", LastName = "Anderson", Country = "AUS" } 11: }; 12:  13: var filteredEmployees = Where(employees, emp => emp.ID % 2 == 0); 14: var formattedEmployees = Select(filteredEmployees); 15:  16: foreach (EmployeeFormatted emp in formattedEmployees) { 17: Console.WriteLine("ID {0} Full_Name {1}", 18: emp.ID, emp.FullName); 19: } 20: Console.ReadLine(); 21: } 22:  23: static IEnumerable<T> Where<T>(IEnumerable<T> source, Func<T, bool> filter) { 24: foreach (var x in source) { 25: if (filter(x)) { 26: yield return x; 27: } 28: } 29: } 30: 31: static IEnumerable<EmployeeFormatted> Select(IEnumerable<Employee> employees) { 32: foreach (var emp in employees) { 33: yield return new EmployeeFormatted { 34: ID = emp.ID, 35: FullName = emp.LastName + ", " + emp.FirstName 36: }; 37: } 38: } 39: } 40:  41: public class Employee { 42: public int ID { get; set;} 43: public string FirstName { get; set;} 44: public string LastName {get; set;} 45: public string Country { get; set; } 46: } 47:  48: public class EmployeeFormatted { 49: public int ID { get; set; } 50: public string FullName {get; set;} 51: } Output: ID 2 Full_Name Ashlock, Jim ID 4 Full_Name Anderson, Jill We have successfully selected employees who have an even ID and then shaped our data with the help of the Select method so that the final result is an IEnumerable<EmployeeFormatted>.  Lets make our Select method more generic so that the user is given the freedom to shape what the output would look like. We can do this, like before, with lambda expressions. Our Select method is changed to accept a delegate as shown below. TSource will be the type of data that comes in and TResult will be the type the user chooses (shape of data) as returned from the selector delegate. 1:  2: static IEnumerable<TResult> Select<TSource, TResult>(IEnumerable<TSource> source, Func<TSource, TResult> selector) { 3: foreach (var x in source) { 4: yield return selector(x); 5: } 6: } We see the new changes to our app. On line 15, we use lambda expression to specify the shape of the data. In this case the shape will be of type EmployeeFormatted. 1:  2: public class Program 3: { 4: [STAThread] 5: static void Main(string[] args) 6: { 7: var employees = new List<Employee> { 8: new Employee { ID = 1, FirstName = "John", LastName = "Wright", Country = "USA" }, 9: new Employee { ID = 2, FirstName = "Jim", LastName = "Ashlock", Country = "UK" }, 10: new Employee { ID = 3, FirstName = "Jane", LastName = "Jackson", Country = "CHE" }, 11: new Employee { ID = 4, FirstName = "Jill", LastName = "Anderson", Country = "AUS" } 12: }; 13:  14: var filteredEmployees = Where(employees, emp => emp.ID % 2 == 0); 15: var formattedEmployees = Select(filteredEmployees, (emp) => 16: new EmployeeFormatted { 17: ID = emp.ID, 18: FullName = emp.LastName + ", " + emp.FirstName 19: }); 20:  21: foreach (EmployeeFormatted emp in formattedEmployees) { 22: Console.WriteLine("ID {0} Full_Name {1}", 23: emp.ID, emp.FullName); 24: } 25: Console.ReadLine(); 26: } 27: 28: static IEnumerable<T> Where<T>(IEnumerable<T> source, Func<T, bool> filter) { 29: foreach (var x in source) { 30: if (filter(x)) { 31: yield return x; 32: } 33: } 34: } 35: 36: static IEnumerable<TResult> Select<TSource, TResult>(IEnumerable<TSource> source, Func<TSource, TResult> selector) { 37: foreach (var x in source) { 38: yield return selector(x); 39: } 40: } 41: } The code outputs the same result as before. On line 14 we filter our data and on line 15 we project our data. What if we wanted to be more expressive and concise? We could combine both line 14 and 15 into one line as shown below. Assuming you had to perform several operations like this on our collection, you would end up with some very unreadable code! 1: var formattedEmployees = Select(Where(employees, emp => emp.ID % 2 == 0), (emp) => 2: new EmployeeFormatted { 3: ID = emp.ID, 4: FullName = emp.LastName + ", " + emp.FirstName 5: }); A cleaner way to write this would be to give the appearance that the Select and Where methods were part of the IEnumerable<T>. This is exactly what extension methods give us. Extension methods have to be defined in a static class. Let us make the Select and Where extension methods on IEnumerable<T> 1: public static class MyExtensionMethods { 2: static IEnumerable<T> Where<T>(this IEnumerable<T> source, Func<T, bool> filter) { 3: foreach (var x in source) { 4: if (filter(x)) { 5: yield return x; 6: } 7: } 8: } 9: 10: static IEnumerable<TResult> Select<TSource, TResult>(this IEnumerable<TSource> source, Func<TSource, TResult> selector) { 11: foreach (var x in source) { 12: yield return selector(x); 13: } 14: } 15: } The creation of the extension method makes the syntax much cleaner as shown below. We can write as many extension methods as we want and keep on chaining them using this technique. 1: var formattedEmployees = employees 2: .Where(emp => emp.ID % 2 == 0) 3: .Select (emp => new EmployeeFormatted { ID = emp.ID, FullName = emp.LastName + ", " + emp.FirstName }); Making these changes and running our code produces the same result. 1: using System; 2: using System.Collections.Generic; 3:  4: public class Program 5: { 6: [STAThread] 7: static void Main(string[] args) 8: { 9: var employees = new List<Employee> { 10: new Employee { ID = 1, FirstName = "John", LastName = "Wright", Country = "USA" }, 11: new Employee { ID = 2, FirstName = "Jim", LastName = "Ashlock", Country = "UK" }, 12: new Employee { ID = 3, FirstName = "Jane", LastName = "Jackson", Country = "CHE" }, 13: new Employee { ID = 4, FirstName = "Jill", LastName = "Anderson", Country = "AUS" } 14: }; 15:  16: var formattedEmployees = employees 17: .Where(emp => emp.ID % 2 == 0) 18: .Select (emp => 19: new EmployeeFormatted { 20: ID = emp.ID, 21: FullName = emp.LastName + ", " + emp.FirstName 22: } 23: ); 24:  25: foreach (EmployeeFormatted emp in formattedEmployees) { 26: Console.WriteLine("ID {0} Full_Name {1}", 27: emp.ID, emp.FullName); 28: } 29: Console.ReadLine(); 30: } 31: } 32:  33: public static class MyExtensionMethods { 34: static IEnumerable<T> Where<T>(this IEnumerable<T> source, Func<T, bool> filter) { 35: foreach (var x in source) { 36: if (filter(x)) { 37: yield return x; 38: } 39: } 40: } 41: 42: static IEnumerable<TResult> Select<TSource, TResult>(this IEnumerable<TSource> source, Func<TSource, TResult> selector) { 43: foreach (var x in source) { 44: yield return selector(x); 45: } 46: } 47: } 48:  49: public class Employee { 50: public int ID { get; set;} 51: public string FirstName { get; set;} 52: public string LastName {get; set;} 53: public string Country { get; set; } 54: } 55:  56: public class EmployeeFormatted { 57: public int ID { get; set; } 58: public string FullName {get; set;} 59: } Let’s change our code to return a collection of anonymous types and get rid of the EmployeeFormatted type. We see that the code produces the same output. 1: using System; 2: using System.Collections.Generic; 3:  4: public class Program 5: { 6: [STAThread] 7: static void Main(string[] args) 8: { 9: var employees = new List<Employee> { 10: new Employee { ID = 1, FirstName = "John", LastName = "Wright", Country = "USA" }, 11: new Employee { ID = 2, FirstName = "Jim", LastName = "Ashlock", Country = "UK" }, 12: new Employee { ID = 3, FirstName = "Jane", LastName = "Jackson", Country = "CHE" }, 13: new Employee { ID = 4, FirstName = "Jill", LastName = "Anderson", Country = "AUS" } 14: }; 15:  16: var formattedEmployees = employees 17: .Where(emp => emp.ID % 2 == 0) 18: .Select (emp => 19: new { 20: ID = emp.ID, 21: FullName = emp.LastName + ", " + emp.FirstName 22: } 23: ); 24:  25: foreach (var emp in formattedEmployees) { 26: Console.WriteLine("ID {0} Full_Name {1}", 27: emp.ID, emp.FullName); 28: } 29: Console.ReadLine(); 30: } 31: } 32:  33: public static class MyExtensionMethods { 34: public static IEnumerable<T> Where<T>(this IEnumerable<T> source, Func<T, bool> filter) { 35: foreach (var x in source) { 36: if (filter(x)) { 37: yield return x; 38: } 39: } 40: } 41: 42: public static IEnumerable<TResult> Select<TSource, TResult>(this IEnumerable<TSource> source, Func<TSource, TResult> selector) { 43: foreach (var x in source) { 44: yield return selector(x); 45: } 46: } 47: } 48:  49: public class Employee { 50: public int ID { get; set;} 51: public string FirstName { get; set;} 52: public string LastName {get; set;} 53: public string Country { get; set; } 54: } To be more expressive, C# allows us to write our extension method calls as a query expression. Line 16 can be rewritten a query expression like so: 1: var formattedEmployees = from emp in employees 2: where emp.ID % 2 == 0 3: select new { 4: ID = emp.ID, 5: FullName = emp.LastName + ", " + emp.FirstName 6: }; When the compiler encounters an expression like the above, it simply rewrites it as calls to our extension methods.  So far we have been using our extension methods. The System.Linq namespace contains several extension methods for objects that implement the IEnumerable<T>. You can see a listing of these methods in the Enumerable class in the System.Linq namespace. Let’s get rid of our extension methods (which I purposefully wrote to be of the same signature as the ones in the Enumerable class) and use the ones provided in the Enumerable class. Our final code is shown below: 1: using System; 2: using System.Collections.Generic; 3: using System.Linq; //Added 4:  5: public class Program 6: { 7: [STAThread] 8: static void Main(string[] args) 9: { 10: var employees = new List<Employee> { 11: new Employee { ID = 1, FirstName = "John", LastName = "Wright", Country = "USA" }, 12: new Employee { ID = 2, FirstName = "Jim", LastName = "Ashlock", Country = "UK" }, 13: new Employee { ID = 3, FirstName = "Jane", LastName = "Jackson", Country = "CHE" }, 14: new Employee { ID = 4, FirstName = "Jill", LastName = "Anderson", Country = "AUS" } 15: }; 16:  17: var formattedEmployees = from emp in employees 18: where emp.ID % 2 == 0 19: select new { 20: ID = emp.ID, 21: FullName = emp.LastName + ", " + emp.FirstName 22: }; 23:  24: foreach (var emp in formattedEmployees) { 25: Console.WriteLine("ID {0} Full_Name {1}", 26: emp.ID, emp.FullName); 27: } 28: Console.ReadLine(); 29: } 30: } 31:  32: public class Employee { 33: public int ID { get; set;} 34: public string FirstName { get; set;} 35: public string LastName {get; set;} 36: public string Country { get; set; } 37: } 38:  39: public class EmployeeFormatted { 40: public int ID { get; set; } 41: public string FullName {get; set;} 42: } This post has shown you a basic overview of LINQ to Objects work by showning you how an expression is converted to a sequence of calls to extension methods when working directly with objects. It gets more interesting when working with LINQ to SQL where an expression tree is constructed – an in memory data representation of the expression. The C# compiler compiles these expressions into code that builds an expression tree at runtime. The provider can then traverse the expression tree and generate the appropriate SQL query. You can read more about expression trees in this MSDN article.

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• MySQL Syslog Audit Plugin

  - by jonathonc

  This post shows the construction process of the Syslog Audit plugin that was presented at MySQL Connect 2012. It is based on an environment that has the appropriate development tools enabled including gcc,g++ and cmake. It also assumes you have downloaded the MySQL source code (5.5.16 or higher) and have compiled and installed the system into the /usr/local/mysql directory ready for use.  The information provided below is designed to show the different components that make up a plugin, and specifically an audit type plugin, and how it comes together to be used within the MySQL service. The MySQL Reference Manual contains information regarding the plugin API and how it can be used, so please refer there for more detailed information. The code in this post is designed to give the simplest information necessary, so handling every return code, managing race conditions etc is not part of this example code. Let's start by looking at the most basic implementation of our plugin code as seen below: /*    Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved.    Author:  Jonathon Coombes    Licence: GPL    Description: An auditing plugin that logs to syslog and                 can adjust the loglevel via the system variables. */ #include <stdio.h> #include <string.h> #include <mysql/plugin_audit.h> #include <syslog.h> There is a commented header detailing copyright/licencing and meta-data information and then the include headers. The two important include statements for our plugin are the syslog.h plugin, which gives us the structures for syslog, and the plugin_audit.h include which has details regarding the audit specific plugin api. Note that we do not need to include the general plugin header plugin.h, as this is done within the plugin_audit.h file already. To implement our plugin within the current implementation we need to add it into our source code and compile. > cd /usr/local/src/mysql-5.5.28/plugin > mkdir audit_syslog > cd audit_syslog A simple CMakeLists.txt file is created to manage the plugin compilation: MYSQL_ADD_PLUGIN(audit_syslog audit_syslog.cc MODULE_ONLY) Run the cmake  command at the top level of the source and then you can compile the plugin using the 'make' command. This results in a compiled audit_syslog.so library, but currently it is not much use to MySQL as there is no level of api defined to communicate with the MySQL service. Now we need to define the general plugin structure that enables MySQL to recognise the library as a plugin and be able to install/uninstall it and have it show up in the system. The structure is defined in the plugin.h file in the MySQL source code.  /*   Plugin library descriptor */ mysql_declare_plugin(audit_syslog) {   MYSQL_AUDIT_PLUGIN,           /* plugin type                    */   &audit_syslog_descriptor,     /* descriptor handle               */   "audit_syslog",               /* plugin name                     */   "Author Name",                /* author                          */   "Simple Syslog Audit",        /* description                     */   PLUGIN_LICENSE_GPL,           /* licence                         */   audit_syslog_init,            /* init function     */   audit_syslog_deinit,          /* deinit function */   0x0001,                       /* plugin version                  */   NULL,                         /* status variables        */   NULL,                         /* system variables                */   NULL,                         /* no reserves                     */   0,                            /* no flags                        */ } mysql_declare_plugin_end; The general plugin descriptor above is standard for all plugin types in MySQL. The plugin type is defined along with the init/deinit functions and interface methods into the system for sharing information, and various other metadata information. The descriptors have an internally recognised version number so that plugins can be matched against the api on the running server. The other details are usually related to the type-specific methods and structures to implement the plugin. Each plugin has a type-specific descriptor as well which details how the plugin is implemented for the specific purpose of that plugin type. /*   Plugin type-specific descriptor */ static struct st_mysql_audit audit_syslog_descriptor= {   MYSQL_AUDIT_INTERFACE_VERSION,                        /* interface version    */   NULL,                                                 /* release_thd function */   audit_syslog_notify,                                  /* notify function      */   { (unsigned long) MYSQL_AUDIT_GENERAL_CLASSMASK |                     MYSQL_AUDIT_CONNECTION_CLASSMASK }  /* class mask           */ }; In this particular case, the release_thd function has not been defined as it is not required. The important method for auditing is the notify function which is activated when an event occurs on the system. The notify function is designed to activate on an event and the implementation will determine how it is handled. For the audit_syslog plugin, the use of the syslog feature sends all events to the syslog for recording. The class mask allows us to determine what type of events are being seen by the notify function. There are currently two major types of event: 1. General Events: This includes general logging, errors, status and result type events. This is the main one for tracking the queries and operations on the database. 2. Connection Events: This group is based around user logins. It monitors connections and disconnections, but also if somebody changes user while connected. With most audit plugins, the principle behind the plugin is to track changes to the system over time and counters can be an important part of this process. The next step is to define and initialise the counters that are used to track the events in the service. There are 3 counters defined in total for our plugin - the # of general events, the # of connection events and the total number of events.  static volatile int total_number_of_calls; /* Count MYSQL_AUDIT_GENERAL_CLASS event instances */ static volatile int number_of_calls_general; /* Count MYSQL_AUDIT_CONNECTION_CLASS event instances */ static volatile int number_of_calls_connection; The init and deinit functions for the plugin are there to be called when the plugin is activated and when it is terminated. These offer the best option to initialise the counters for our plugin: /*  Initialize the plugin at server start or plugin installation. */ static int audit_syslog_init(void *arg __attribute__((unused))) {     openlog("mysql_audit:",LOG_PID|LOG_PERROR|LOG_CONS,LOG_USER);     total_number_of_calls= 0;     number_of_calls_general= 0;     number_of_calls_connection= 0;     return(0); } The init function does a call to openlog to initialise the syslog functionality. The parameters are the service to log under ("mysql_audit" in this case), the syslog flags and the facility for the logging. Then each of the counters are initialised to zero and a success is returned. If the init function is not defined, it will return success by default. /*  Terminate the plugin at server shutdown or plugin deinstallation. */ static int audit_syslog_deinit(void *arg __attribute__((unused))) {     closelog();     return(0); } The deinit function will simply close our syslog connection and return success. Note that the syslog functionality is part of the glibc libraries and does not require any external factors.  The function names are what we define in the general plugin structure, so these have to match otherwise there will be errors. The next step is to implement the event notifier function that was defined in the type specific descriptor (audit_syslog_descriptor) which is audit_syslog_notify. /* Event notifier function */ static void audit_syslog_notify(MYSQL_THD thd __attribute__((unused)), unsigned int event_class, const void *event) { total_number_of_calls++; if (event_class == MYSQL_AUDIT_GENERAL_CLASS) { const struct mysql_event_general *event_general= (const struct mysql_event_general *) event; number_of_calls_general++; syslog(audit_loglevel,"%lu: User: %s Command: %s Query: %s\n", event_general->general_thread_id, event_general->general_user, event_general->general_command, event_general->general_query ); } else if (event_class == MYSQL_AUDIT_CONNECTION_CLASS) { const struct mysql_event_connection *event_connection= (const struct mysql_event_connection *) event; number_of_calls_connection++; syslog(audit_loglevel,"%lu: User: %s@%s[%s] Event: %d Status: %d\n", event_connection->thread_id, event_connection->user, event_connection->host, event_connection->ip, event_connection->event_subclass, event_connection->status ); } }   In the case of an event, the notifier function is called. The first step is to increment the total number of events that have occurred in our database.The event argument is then cast into the appropriate event structure depending on the class type, of general event or connection event. The event type counters are incremented and details are sent via the syslog() function out to the system log. There are going to be different line formats and information returned since the general events have different data compared to the connection events, even though some of the details overlap, for example, user, thread id, host etc. On compiling the code now, there should be no errors and the resulting audit_syslog.so can be loaded into the server and ready to use. Log into the server and type: mysql> INSTALL PLUGIN audit_syslog SONAME 'audit_syslog.so'; This will install the plugin and will start updating the syslog immediately. Note that the audit plugin attaches to the immediate thread and cannot be uninstalled while that thread is active. This means that you cannot run the UNISTALL command until you log into a different connection (thread) on the server. Once the plugin is loaded, the system log will show output such as the following: Oct  8 15:33:21 machine mysql_audit:[8337]: 87: User: root[root] @ localhost []  Command: (null)  Query: INSTALL PLUGIN audit_syslog SONAME 'audit_syslog.so' Oct  8 15:33:21 machine mysql_audit:[8337]: 87: User: root[root] @ localhost []  Command: Query  Query: INSTALL PLUGIN audit_syslog SONAME 'audit_syslog.so' Oct  8 15:33:40 machine mysql_audit:[8337]: 87: User: root[root] @ localhost []  Command: (null)  Query: show tables Oct  8 15:33:40 machine mysql_audit:[8337]: 87: User: root[root] @ localhost []  Command: Query  Query: show tables Oct  8 15:33:43 machine mysql_audit:[8337]: 87: User: root[root] @ localhost []  Command: (null)  Query: select * from t1 Oct  8 15:33:43 machine mysql_audit:[8337]: 87: User: root[root] @ localhost []  Command: Query  Query: select * from t1 It appears that two of each event is being shown, but in actuality, these are two separate event types - the result event and the status event. This could be refined further by changing the audit_syslog_notify function to handle the different event sub-types in a different manner.  So far, it seems that the logging is working with events showing up in the syslog output. The issue now is that the counters created earlier to track the number of events by type are not accessible when the plugin is being run. Instead there needs to be a way to expose the plugin specific information to the service and vice versa. This could be done via the information_schema plugin api, but for something as simple as counters, the obvious choice is the system status variables. This is done using the standard structure and the declaration: /*  Plugin status variables for SHOW STATUS */ static struct st_mysql_show_var audit_syslog_status[]= {   { "Audit_syslog_total_calls",     (char *) &total_number_of_calls,     SHOW_INT },   { "Audit_syslog_general_events",     (char *) &number_of_calls_general,     SHOW_INT },   { "Audit_syslog_connection_events",     (char *) &number_of_calls_connection,     SHOW_INT },   { 0, 0, SHOW_INT } };   The structure is simply the name that will be displaying in the mysql service, the address of the associated variables, and the data type being used for the counter. It is finished with a blank structure to show that there are no more variables. Remember that status variables may have the same name for variables from other plugin, so it is considered appropriate to add the plugin name at the start of the status variable name to avoid confusion. Looking at the status variables in the mysql client shows something like the following: mysql> show global status like "audit%"; +--------------------------------+-------+ | Variable_name                  | Value | +--------------------------------+-------+ | Audit_syslog_connection_events | 1     | | Audit_syslog_general_events    | 2     | | Audit_syslog_total_calls       | 3     | +--------------------------------+-------+ 3 rows in set (0.00 sec) The final connectivity piece for the plugin is to allow the interactive change of the logging level between the plugin and the system. This requires the ability to send changes via the mysql service through to the plugin. This is done using the system variables interface and defining a single variable to keep track of the active logging level for the facility. /* Plugin system variables for SHOW VARIABLES */ static MYSQL_SYSVAR_STR(loglevel, audit_loglevel,                         PLUGIN_VAR_RQCMDARG,                         "User can specify the log level for auditing",                         audit_loglevel_check, audit_loglevel_update, "LOG_NOTICE"); static struct st_mysql_sys_var* audit_syslog_sysvars[] = {     MYSQL_SYSVAR(loglevel),     NULL }; So now the system variable 'loglevel' is defined for the plugin and associated to the global variable 'audit_loglevel'. The check or validation function is defined to make sure that no garbage values are attempted in the update of the variable. The update function is used to save the new value to the variable. Note that the audit_syslog_sysvars structure is defined in the general plugin descriptor to associate the link between the plugin and the system and how much they interact. Next comes the implementation of the validation function and the update function for the system variable. It is worth noting that if you have a simple numeric such as integers for the variable types, the validate function is often not required as MySQL will handle the automatic check and validation of simple types. /* longest valid value */ #define MAX_LOGLEVEL_SIZE 100 /* hold the valid values */ static const char *possible_modes[]= { "LOG_ERROR", "LOG_WARNING", "LOG_NOTICE", NULL };  static int audit_loglevel_check(     THD*                        thd,    /*!< in: thread handle */     struct st_mysql_sys_var*    var,    /*!< in: pointer to system                                         variable */     void*                       save,   /*!< out: immediate result                                         for update function */     struct st_mysql_value*      value)  /*!< in: incoming string */ {     char buff[MAX_LOGLEVEL_SIZE];     const char *str;     const char **found;     int length;     length= sizeof(buff);     if (!(str= value->val_str(value, buff, &length)))         return 1;     /*         We need to return a pointer to a locally allocated value in "save".         Here we pick to search for the supplied value in an global array of         constant strings and return a pointer to one of them.         The other possiblity is to use the thd_alloc() function to allocate         a thread local buffer instead of the global constants.     */     for (found= possible_modes; *found; found++)     {         if (!strcmp(*found, str))         {             *(const char**)save= *found;             return 0;         }     }     return 1; } The validation function is simply to take the value being passed in via the SET GLOBAL VARIABLE command and check if it is one of the pre-defined values allowed  in our possible_values array. If it is found to be valid, then the value is assigned to the save variable ready for passing through to the update function. static void audit_loglevel_update(     THD*                        thd,        /*!< in: thread handle */     struct st_mysql_sys_var*    var,        /*!< in: system variable                                             being altered */     void*                       var_ptr,    /*!< out: pointer to                                             dynamic variable */     const void*                 save)       /*!< in: pointer to                                             temporary storage */ {     /* assign the new value so that the server can read it */     *(char **) var_ptr= *(char **) save;     /* assign the new value to the internal variable */     audit_loglevel= *(char **) save; } Since all the validation has been done already, the update function is quite simple for this plugin. The first part is to update the system variable pointer so that the server can read the value. The second part is to update our own global plugin variable for tracking the value. Notice that the save variable is passed in as a void type to allow handling of various data types, so it must be cast to the appropriate data type when assigning it to the variables. Looking at how the latest changes affect the usage of the plugin and the interaction within the server shows: mysql> show global variables like "audit%"; +-----------------------+------------+ | Variable_name         | Value      | +-----------------------+------------+ | audit_syslog_loglevel | LOG_NOTICE | +-----------------------+------------+ 1 row in set (0.00 sec) mysql> set global audit_syslog_loglevel="LOG_ERROR"; Query OK, 0 rows affected (0.00 sec) mysql> show global status like "audit%"; +--------------------------------+-------+ | Variable_name                  | Value | +--------------------------------+-------+ | Audit_syslog_connection_events | 1     | | Audit_syslog_general_events    | 11    | | Audit_syslog_total_calls       | 12    | +--------------------------------+-------+ 3 rows in set (0.00 sec) mysql> show global variables like "audit%"; +-----------------------+-----------+ | Variable_name         | Value     | +-----------------------+-----------+ | audit_syslog_loglevel | LOG_ERROR | +-----------------------+-----------+ 1 row in set (0.00 sec)   So now we have a plugin that will audit the events on the system and log the details to the system log. It allows for interaction to see the number of different events within the server details and provides a mechanism to change the logging level interactively via the standard system methods of the SET command. A more complex auditing plugin may have more detailed code, but each of the above areas is what will be involved and simply expanded on to add more functionality. With the above skeleton code, it is now possible to create your own audit plugins to implement your own auditing requirements. If, however, you are not of the coding persuasion, then you could always consider the option of the MySQL Enterprise Audit plugin that is available to purchase.

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• Debian squeeze keyboard and touchpad not working / detected on laptop

  - by Esa

  They work before gdm3 starts. a connected mouse also stops working, but functions after removal and re-plug. no xorg.conf. log doesn't show any loading of drivers for kbd/touchpad [ 33.783] X.Org X Server 1.10.4 Release Date: 2011-08-19 [ 33.783] X Protocol Version 11, Revision 0 [ 33.783] Build Operating System: Linux 3.0.0-1-amd64 x86_64 Debian [ 33.783] Current Operating System: Linux sus 3.2.0-0.bpo.2-amd64 #1 SMP Sun Mar 25 10:33:35 UTC 2012 x86_64 [ 33.783] Kernel command line: BOOT_IMAGE=/boot/vmlinuz-3.2.0-0.bpo.2-amd64 root=UUID=8686f840-d165-4d1e-b995-2ebbd94aa3d2 ro quiet [ 33.783] Build Date: 28 August 2011 09:39:43PM [ 33.783] xorg-server 2:1.10.4-1~bpo60+1 (Cyril Brulebois <[email protected]>) [ 33.783] Current version of pixman: 0.16.4 [ 33.783] Before reporting problems, check http://wiki.x.org to make sure that you have the latest version. [ 33.783] Markers: (--) probed, (**) from config file, (==) default setting, (++) from command line, (!!) notice, (II) informational, (WW) warning, (EE) error, (NI) not implemented, (??) unknown. [ 33.783] (==) Log file: "/var/log/Xorg.0.log", Time: Wed Mar 28 09:34:04 2012 [ 33.837] (==) Using system config directory "/usr/share/X11/xorg.conf.d" [ 33.936] (==) No Layout section. Using the first Screen section. [ 33.936] (==) No screen section available. Using defaults. [ 33.936] (**) |-->Screen "Default Screen Section" (0) [ 33.936] (**) | |-->Monitor "<default monitor>" [ 33.936] (==) No monitor specified for screen "Default Screen Section". Using a default monitor configuration. [ 33.936] (==) Automatically adding devices [ 33.936] (==) Automatically enabling devices [ 34.164] (WW) The directory "/usr/share/fonts/X11/cyrillic" does not exist. [ 34.164] Entry deleted from font path. [ 34.226] (==) FontPath set to: /usr/share/fonts/X11/misc, /usr/share/fonts/X11/100dpi/:unscaled, /usr/share/fonts/X11/75dpi/:unscaled, /usr/share/fonts/X11/Type1, /usr/share/fonts/X11/100dpi, /usr/share/fonts/X11/75dpi, /var/lib/defoma/x-ttcidfont-conf.d/dirs/TrueType, built-ins [ 34.226] (==) ModulePath set to "/usr/lib/xorg/modules" [ 34.226] (II) The server relies on udev to provide the list of input devices. If no devices become available, reconfigure udev or disable AutoAddDevices. [ 34.226] (II) Loader magic: 0x7d3ae0 [ 34.226] (II) Module ABI versions: [ 34.226] X.Org ANSI C Emulation: 0.4 [ 34.226] X.Org Video Driver: 10.0 [ 34.226] X.Org XInput driver : 12.2 [ 34.226] X.Org Server Extension : 5.0 [ 34.227] (--) PCI:*(0:1:5:0) 1002:9712:103c:1661 rev 0, Mem @ 0xd0000000/268435456, 0xf1400000/65536, 0xf1300000/1048576, I/O @ 0x00008000/256 [ 34.227] (--) PCI: (0:2:0:0) 1002:6760:103c:1661 rev 0, Mem @ 0xe0000000/268435456, 0xf0300000/131072, I/O @ 0x00004000/256, BIOS @ 0x????????/131072 [ 34.227] (II) Open ACPI successful (/var/run/acpid.socket) [ 34.227] (II) LoadModule: "extmod" [ 34.249] (II) Loading /usr/lib/xorg/modules/extensions/libextmod.so [ 34.277] (II) Module extmod: vendor="X.Org Foundation" [ 34.277] compiled for 1.10.4, module version = 1.0.0 [ 34.277] Module class: X.Org Server Extension [ 34.277] ABI class: X.Org Server Extension, version 5.0 [ 34.277] (II) Loading extension SELinux [ 34.277] (II) Loading extension MIT-SCREEN-SAVER [ 34.277] (II) Loading extension XFree86-VidModeExtension [ 34.277] (II) Loading extension XFree86-DGA [ 34.277] (II) Loading extension DPMS [ 34.277] (II) Loading extension XVideo [ 34.277] (II) Loading extension XVideo-MotionCompensation [ 34.277] (II) Loading extension X-Resource [ 34.277] (II) LoadModule: "dbe" [ 34.277] (II) Loading /usr/lib/xorg/modules/extensions/libdbe.so [ 34.299] (II) Module dbe: vendor="X.Org Foundation" [ 34.299] compiled for 1.10.4, module version = 1.0.0 [ 34.299] Module class: X.Org Server Extension [ 34.299] ABI class: X.Org Server Extension, version 5.0 [ 34.299] (II) Loading extension DOUBLE-BUFFER [ 34.299] (II) LoadModule: "glx" [ 34.299] (II) Loading /usr/lib/xorg/modules/extensions/libglx.so [ 34.477] (II) Module glx: vendor="X.Org Foundation" [ 34.477] compiled for 1.10.4, module version = 1.0.0 [ 34.477] ABI class: X.Org Server Extension, version 5.0 [ 34.477] (==) AIGLX enabled [ 34.477] (II) Loading extension GLX [ 34.477] (II) LoadModule: "record" [ 34.478] (II) Loading /usr/lib/xorg/modules/extensions/librecord.so [ 34.481] (II) Module record: vendor="X.Org Foundation" [ 34.481] compiled for 1.10.4, module version = 1.13.0 [ 34.481] Module class: X.Org Server Extension [ 34.481] ABI class: X.Org Server Extension, version 5.0 [ 34.481] (II) Loading extension RECORD [ 34.481] (II) LoadModule: "dri" [ 34.481] (II) Loading /usr/lib/xorg/modules/extensions/libdri.so [ 34.512] (II) Module dri: vendor="X.Org Foundation" [ 34.512] compiled for 1.10.4, module version = 1.0.0 [ 34.512] ABI class: X.Org Server Extension, version 5.0 [ 34.512] (II) Loading extension XFree86-DRI [ 34.512] (II) LoadModule: "dri2" [ 34.512] (II) Loading /usr/lib/xorg/modules/extensions/libdri2.so [ 34.515] (II) Module dri2: vendor="X.Org Foundation" [ 34.515] compiled for 1.10.4, module version = 1.2.0 [ 34.515] ABI class: X.Org Server Extension, version 5.0 [ 34.515] (II) Loading extension DRI2 [ 34.515] (==) Matched ati as autoconfigured driver 0 [ 34.515] (==) Matched vesa as autoconfigured driver 1 [ 34.515] (==) Matched fbdev as autoconfigured driver 2 [ 34.515] (==) Assigned the driver to the xf86ConfigLayout [ 34.515] (II) LoadModule: "ati" [ 34.706] (II) Loading /usr/lib/xorg/modules/drivers/ati_drv.so [ 34.724] (II) Module ati: vendor="X.Org Foundation" [ 34.724] compiled for 1.10.3, module version = 6.14.2 [ 34.724] Module class: X.Org Video Driver [ 34.724] ABI class: X.Org Video Driver, version 10.0 [ 34.724] (II) LoadModule: "radeon" [ 34.725] (II) Loading /usr/lib/xorg/modules/drivers/radeon_drv.so [ 34.923] (II) Module radeon: vendor="X.Org Foundation" [ 34.923] compiled for 1.10.3, module version = 6.14.2 [ 34.923] Module class: X.Org Video Driver [ 34.923] ABI class: X.Org Video Driver, version 10.0 [ 34.945] (II) LoadModule: "vesa" [ 34.945] (II) Loading /usr/lib/xorg/modules/drivers/vesa_drv.so [ 34.988] (II) Module vesa: vendor="X.Org Foundation" [ 34.988] compiled for 1.10.3, module version = 2.3.0 [ 34.988] Module class: X.Org Video Driver [ 34.988] ABI class: X.Org Video Driver, version 10.0 [ 34.988] (II) LoadModule: "fbdev" [ 34.988] (II) Loading /usr/lib/xorg/modules/drivers/fbdev_drv.so [ 35.020] (II) Module fbdev: vendor="X.Org Foundation" [ 35.020] compiled for 1.10.3, module version = 0.4.2 [ 35.020] ABI class: X.Org Video Driver, version 10.0 [ 35.020] (II) RADEON: Driver for ATI Radeon chipsets: <snip> [ 35.023] (II) VESA: driver for VESA chipsets: vesa [ 35.023] (II) FBDEV: driver for framebuffer: fbdev [ 35.023] (++) using VT number 7 [ 35.033] (II) Loading /usr/lib/xorg/modules/drivers/radeon_drv.so [ 35.033] (II) [KMS] Kernel modesetting enabled. [ 35.033] (WW) Falling back to old probe method for vesa [ 35.034] (WW) Falling back to old probe method for fbdev [ 35.034] (II) Loading sub module "fbdevhw" [ 35.034] (II) LoadModule: "fbdevhw" [ 35.034] (II) Loading /usr/lib/xorg/modules/libfbdevhw.so [ 35.185] (II) Module fbdevhw: vendor="X.Org Foundation" [ 35.185] compiled for 1.10.4, module version = 0.0.2 [ 35.185] ABI class: X.Org Video Driver, version 10.0 [ 35.288] (II) RADEON(0): Creating default Display subsection in Screen section "Default Screen Section" for depth/fbbpp 24/32 [ 35.288] (==) RADEON(0): Depth 24, (--) framebuffer bpp 32 [ 35.288] (II) RADEON(0): Pixel depth = 24 bits stored in 4 bytes (32 bpp pixmaps) [ 35.288] (==) RADEON(0): Default visual is TrueColor [ 35.288] (==) RADEON(0): RGB weight 888 [ 35.288] (II) RADEON(0): Using 8 bits per RGB (8 bit DAC) [ 35.288] (--) RADEON(0): Chipset: "ATI Mobility Radeon HD 4200" (ChipID = 0x9712) [ 35.288] (II) RADEON(0): PCI card detected [ 35.288] drmOpenDevice: node name is /dev/dri/card0 [ 35.288] drmOpenDevice: open result is 9, (OK) [ 35.288] drmOpenByBusid: Searching for BusID pci:0000:01:05.0 [ 35.288] drmOpenDevice: node name is /dev/dri/card0 [ 35.288] drmOpenDevice: open result is 9, (OK) [ 35.288] drmOpenByBusid: drmOpenMinor returns 9 [ 35.288] drmOpenByBusid: drmGetBusid reports pci:0000:01:05.0 [ 35.288] (II) Loading sub module "exa" [ 35.288] (II) LoadModule: "exa" [ 35.288] (II) Loading /usr/lib/xorg/modules/libexa.so [ 35.335] (II) Module exa: vendor="X.Org Foundation" [ 35.335] compiled for 1.10.4, module version = 2.5.0 [ 35.335] ABI class: X.Org Video Driver, version 10.0 [ 35.335] (II) RADEON(0): KMS Color Tiling: disabled [ 35.335] (II) RADEON(0): KMS Pageflipping: enabled [ 35.335] (II) RADEON(0): SwapBuffers wait for vsync: enabled [ 35.360] (II) RADEON(0): Output VGA-0 has no monitor section [ 35.360] (II) RADEON(0): Output LVDS has no monitor section [ 35.364] (II) RADEON(0): Output HDMI-0 has no monitor section [ 35.388] (II) RADEON(0): EDID for output VGA-0 [ 35.388] (II) RADEON(0): EDID for output LVDS [ 35.388] (II) RADEON(0): Manufacturer: LGD Model: 2ac Serial#: 0 [ 35.388] (II) RADEON(0): Year: 2010 Week: 0 [ 35.388] (II) RADEON(0): EDID Version: 1.3 [ 35.388] (II) RADEON(0): Digital Display Input [ 35.388] (II) RADEON(0): Max Image Size [cm]: horiz.: 34 vert.: 19 [ 35.388] (II) RADEON(0): Gamma: 2.20 [ 35.388] (II) RADEON(0): No DPMS capabilities specified [ 35.388] (II) RADEON(0): Supported color encodings: RGB 4:4:4 YCrCb 4:4:4 [ 35.388] (II) RADEON(0): First detailed timing is preferred mode [ 35.388] (II) RADEON(0): redX: 0.616 redY: 0.371 greenX: 0.355 greenY: 0.606 [ 35.388] (II) RADEON(0): blueX: 0.152 blueY: 0.100 whiteX: 0.313 whiteY: 0.329 [ 35.388] (II) RADEON(0): Manufacturer's mask: 0 [ 35.388] (II) RADEON(0): Supported detailed timing: [ 35.388] (II) RADEON(0): clock: 69.3 MHz Image Size: 344 x 194 mm [ 35.388] (II) RADEON(0): h_active: 1366 h_sync: 1398 h_sync_end 1430 h_blank_end 1486 h_border: 0 [ 35.388] (II) RADEON(0): v_active: 768 v_sync: 770 v_sync_end 774 v_blanking: 782 v_border: 0 [ 35.388] (II) RADEON(0): LG Display [ 35.388] (II) RADEON(0): LP156WH2-TLQB [ 35.388] (II) RADEON(0): EDID (in hex): [ 35.388] (II) RADEON(0): 00ffffffffffff0030e4ac0200000000 [ 35.388] (II) RADEON(0): 00140103802213780ac1259d5f5b9b27 [ 35.388] (II) RADEON(0): 19505400000001010101010101010101 [ 35.388] (II) RADEON(0): 010101010101121b567850000e302020 [ 35.388] (II) RADEON(0): 240058c2100000190000000000000000 [ 35.388] (II) RADEON(0): 00000000000000000000000000fe004c [ 35.388] (II) RADEON(0): 4720446973706c61790a2020000000fe [ 35.388] (II) RADEON(0): 004c503135365748322d544c514200c1 [ 35.388] (II) RADEON(0): Printing probed modes for output LVDS [ 35.388] (II) RADEON(0): Modeline "1366x768"x59.6 69.30 1366 1398 1430 1486 768 770 774 782 -hsync -vsync (46.6 kHz) [ 35.388] (II) RADEON(0): Modeline "1280x720"x59.9 74.50 1280 1344 1472 1664 720 723 728 748 -hsync +vsync (44.8 kHz) [ 35.388] (II) RADEON(0): Modeline "1152x768"x59.8 71.75 1152 1216 1328 1504 768 771 781 798 -hsync +vsync (47.7 kHz) [ 35.388] (II) RADEON(0): Modeline "1024x768"x59.9 63.50 1024 1072 1176 1328 768 771 775 798 -hsync +vsync (47.8 kHz) [ 35.388] (II) RADEON(0): Modeline "800x600"x59.9 38.25 800 832 912 1024 600 603 607 624 -hsync +vsync (37.4 kHz) [ 35.388] (II) RADEON(0): Modeline "848x480"x59.7 31.50 848 872 952 1056 480 483 493 500 -hsync +vsync (29.8 kHz) [ 35.388] (II) RADEON(0): Modeline "720x480"x59.7 26.75 720 744 808 896 480 483 493 500 -hsync +vsync (29.9 kHz) [ 35.388] (II) RADEON(0): Modeline "640x480"x59.4 23.75 640 664 720 800 480 483 487 500 -hsync +vsync (29.7 kHz) [ 35.392] (II) RADEON(0): EDID for output HDMI-0 [ 35.392] (II) RADEON(0): Output VGA-0 disconnected [ 35.392] (II) RADEON(0): Output LVDS connected [ 35.392] (II) RADEON(0): Output HDMI-0 disconnected [ 35.392] (II) RADEON(0): Using exact sizes for initial modes [ 35.392] (II) RADEON(0): Output LVDS using initial mode 1366x768 [ 35.392] (II) RADEON(0): Using default gamma of (1.0, 1.0, 1.0) unless otherwise stated. [ 35.392] (II) RADEON(0): mem size init: gart size :1fdff000 vram size: s:10000000 visible:fba0000 [ 35.392] (II) RADEON(0): EXA: Driver will allow EXA pixmaps in VRAM [ 35.392] (==) RADEON(0): DPI set to (96, 96) [ 35.392] (II) Loading sub module "fb" [ 35.392] (II) LoadModule: "fb" [ 35.392] (II) Loading /usr/lib/xorg/modules/libfb.so [ 35.492] (II) Module fb: vendor="X.Org Foundation" [ 35.492] compiled for 1.10.4, module version = 1.0.0 [ 35.492] ABI class: X.Org ANSI C Emulation, version 0.4 [ 35.492] (II) Loading sub module "ramdac" [ 35.492] (II) LoadModule: "ramdac" [ 35.492] (II) Module "ramdac" already built-in [ 35.492] (II) UnloadModule: "vesa" [ 35.492] (II) Unloading vesa [ 35.492] (II) UnloadModule: "fbdev" [ 35.492] (II) Unloading fbdev [ 35.492] (II) UnloadModule: "fbdevhw" [ 35.492] (II) Unloading fbdevhw [ 35.492] (--) Depth 24 pixmap format is 32 bpp [ 35.492] (II) RADEON(0): [DRI2] Setup complete [ 35.492] (II) RADEON(0): [DRI2] DRI driver: r600 [ 35.492] (II) RADEON(0): Front buffer size: 4224K [ 35.492] (II) RADEON(0): VRAM usage limit set to 228096K [ 35.615] (==) RADEON(0): Backing store disabled [ 35.615] (II) RADEON(0): Direct rendering enabled [ 35.658] (II) RADEON(0): Setting EXA maxPitchBytes [ 35.658] (II) EXA(0): Driver allocated offscreen pixmaps [ 35.658] (II) EXA(0): Driver registered support for the following operations: [ 35.658] (II) Solid [ 35.658] (II) Copy [ 35.658] (II) Composite (RENDER acceleration) [ 35.658] (II) UploadToScreen [ 35.658] (II) DownloadFromScreen [ 35.687] (II) RADEON(0): Acceleration enabled [ 35.687] (==) RADEON(0): DPMS enabled [ 35.687] (==) RADEON(0): Silken mouse enabled [ 35.721] (II) RADEON(0): Set up textured video [ 35.721] (II) RADEON(0): RandR 1.2 enabled, ignore the following RandR disabled message. [ 35.721] (--) RandR disabled [ 35.721] (II) Initializing built-in extension Generic Event Extension [ 35.721] (II) Initializing built-in extension SHAPE [ 35.721] (II) Initializing built-in extension MIT-SHM [ 35.721] (II) Initializing built-in extension XInputExtension [ 35.721] (II) Initializing built-in extension XTEST [ 35.721] (II) Initializing built-in extension BIG-REQUESTS [ 35.721] (II) Initializing built-in extension SYNC [ 35.721] (II) Initializing built-in extension XKEYBOARD [ 35.721] (II) Initializing built-in extension XC-MISC [ 35.721] (II) Initializing built-in extension SECURITY [ 35.721] (II) Initializing built-in extension XINERAMA [ 35.721] (II) Initializing built-in extension XFIXES [ 35.721] (II) Initializing built-in extension RENDER [ 35.721] (II) Initializing built-in extension RANDR [ 35.721] (II) Initializing built-in extension COMPOSITE [ 35.721] (II) Initializing built-in extension DAMAGE [ 35.721] (II) SELinux: Disabled on system [ 35.982] (II) AIGLX: enabled GLX_MESA_copy_sub_buffer [ 35.982] (II) AIGLX: enabled GLX_INTEL_swap_event [ 35.982] (II) AIGLX: enabled GLX_SGI_swap_control and GLX_MESA_swap_control [ 35.982] (II) AIGLX: enabled GLX_SGI_make_current_read [ 35.982] (II) AIGLX: GLX_EXT_texture_from_pixmap backed by buffer objects [ 35.982] (II) AIGLX: Loaded and initialized /usr/lib/dri/r600_dri.so [ 35.982] (II) GLX: Initialized DRI2 GL provider for screen 0 [ 35.999] (II) RADEON(0): Setting screen physical size to 361 x 203 [ 43.896] (II) RADEON(0): EDID vendor "LGD", prod id 684 [ 43.896] (II) RADEON(0): Printing DDC gathered Modelines: [ 43.896] (II) RADEON(0): Modeline "1366x768"x0.0 69.30 1366 1398 1430 1486 768 770 774 782 -hsync -vsync (46.6 kHz) [ 43.924] (II) RADEON(0): EDID vendor "LGD", prod id 684 [ 43.924] (II) RADEON(0): Printing DDC gathered Modelines: [ 43.924] (II) RADEON(0): Modeline "1366x768"x0.0 69.30 1366 1398 1430 1486 768 770 774 782 -hsync -vsync (46.6 kHz) [ 43.988] (II) RADEON(0): EDID vendor "LGD", prod id 684 [ 43.988] (II) RADEON(0): Printing DDC gathered Modelines: [ 43.988] (II) RADEON(0): Modeline "1366x768"x0.0 69.30 1366 1398 1430 1486 768 770 774 782 -hsync -vsync (46.6 kHz) [ 67.375] (II) config/udev: Adding input device Logitech USB Optical Mouse (/dev/input/event1) [ 67.376] (**) Logitech USB Optical Mouse: Applying InputClass "evdev pointer catchall" [ 67.376] (II) LoadModule: "evdev" [ 67.376] (II) Loading /usr/lib/xorg/modules/input/evdev_drv.so [ 67.392] (II) Module evdev: vendor="X.Org Foundation" [ 67.392] compiled for 1.10.3, module version = 2.6.0 [ 67.392] Module class: X.Org XInput Driver [ 67.392] ABI class: X.Org XInput driver, version 12.2 [ 67.392] (II) Using input driver 'evdev' for 'Logitech USB Optical Mouse' [ 67.392] (II) Loading /usr/lib/xorg/modules/input/evdev_drv.so [ 67.392] (**) Logitech USB Optical Mouse: always reports core events [ 67.392] (**) Logitech USB Optical Mouse: Device: "/dev/input/event1" [ 67.392] (--) Logitech USB Optical Mouse: Found 12 mouse buttons [ 67.392] (--) Logitech USB Optical Mouse: Found scroll wheel(s) [ 67.392] (--) Logitech USB Optical Mouse: Found relative axes [ 67.392] (--) Logitech USB Optical Mouse: Found x and y relative axes [ 67.392] (II) Logitech USB Optical Mouse: Configuring as mouse [ 67.392] (II) Logitech USB Optical Mouse: Adding scrollwheel support [ 67.392] (**) Logitech USB Optical Mouse: YAxisMapping: buttons 4 and 5 [ 67.392] (**) Logitech USB Optical Mouse: EmulateWheelButton: 4, EmulateWheelInertia: 10, EmulateWheelTimeout: 200 [ 67.392] (**) Option "config_info" "udev:/sys/devices/pci0000:00/0000:00:13.0/usb5/5-1/5-1:1.0/input/input14/event1" [ 67.392] (II) XINPUT: Adding extended input device "Logitech USB Optical Mouse" (type: MOUSE) [ 67.392] (II) Logitech USB Optical Mouse: initialized for relative axes. [ 67.392] (**) Logitech USB Optical Mouse: (accel) keeping acceleration scheme 1 [ 67.392] (**) Logitech USB Optical Mouse: (accel) acceleration profile 0 [ 67.392] (**) Logitech USB Optical Mouse: (accel) acceleration factor: 2.000 [ 67.392] (**) Logitech USB Optical Mouse: (accel) acceleration threshold: 4 [ 67.392] (II) config/udev: Adding input device Logitech USB Optical Mouse (/dev/input/mouse0) [ 67.392] (II) No input driver/identifier specified (ignoring) [ 78.692] (II) Logitech USB Optical Mouse: Close [ 78.692] (II) UnloadModule: "evdev" [ 78.692] (II) Unloading evdev

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• An Xml Serializable PropertyBag Dictionary Class for .NET

  - by Rick Strahl

  I don't know about you but I frequently need property bags in my applications to store and possibly cache arbitrary data. Dictionary<T,V> works well for this although I always seem to be hunting for a more specific generic type that provides a string key based dictionary. There's string dictionary, but it only works with strings. There's Hashset<T> but it uses the actual values as keys. In most key value pair situations for me string is key value to work off. Dictionary<T,V> works well enough, but there are some issues with serialization of dictionaries in .NET. The .NET framework doesn't do well serializing IDictionary objects out of the box. The XmlSerializer doesn't support serialization of IDictionary via it's default serialization, and while the DataContractSerializer does support IDictionary serialization it produces some pretty atrocious XML. What doesn't work? First off Dictionary serialization with the Xml Serializer doesn't work so the following fails: [TestMethod] public void DictionaryXmlSerializerTest() { var bag = new Dictionary<string, object>(); bag.Add("key", "Value"); bag.Add("Key2", 100.10M); bag.Add("Key3", Guid.NewGuid()); bag.Add("Key4", DateTime.Now); bag.Add("Key5", true); bag.Add("Key7", new byte[3] { 42, 45, 66 }); TestContext.WriteLine(this.ToXml(bag)); } public string ToXml(object obj) { if (obj == null) return null; StringWriter sw = new StringWriter(); XmlSerializer ser = new XmlSerializer(obj.GetType()); ser.Serialize(sw, obj); return sw.ToString(); } The error you get with this is: System.NotSupportedException: The type System.Collections.Generic.Dictionary`2[[System.String, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089],[System.Object, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]] is not supported because it implements IDictionary. Got it! BTW, the same is true with binary serialization. Running the same code above against the DataContractSerializer does work: [TestMethod] public void DictionaryDataContextSerializerTest() { var bag = new Dictionary<string, object>(); bag.Add("key", "Value"); bag.Add("Key2", 100.10M); bag.Add("Key3", Guid.NewGuid()); bag.Add("Key4", DateTime.Now); bag.Add("Key5", true); bag.Add("Key7", new byte[3] { 42, 45, 66 }); TestContext.WriteLine(this.ToXmlDcs(bag)); } public string ToXmlDcs(object value, bool throwExceptions = false) { var ser = new DataContractSerializer(value.GetType(), null, int.MaxValue, true, false, null); MemoryStream ms = new MemoryStream(); ser.WriteObject(ms, value); return Encoding.UTF8.GetString(ms.ToArray(), 0, (int)ms.Length); } This DOES work but produces some pretty heinous XML (formatted with line breaks and indentation here): <ArrayOfKeyValueOfstringanyType xmlns="http://schemas.microsoft.com/2003/10/Serialization/Arrays" xmlns:i="http://www.w3.org/2001/XMLSchema-instance"> <KeyValueOfstringanyType> <Key>key</Key> <Value i:type="a:string" xmlns:a="http://www.w3.org/2001/XMLSchema">Value</Value> </KeyValueOfstringanyType> <KeyValueOfstringanyType> <Key>Key2</Key> <Value i:type="a:decimal" xmlns:a="http://www.w3.org/2001/XMLSchema">100.10</Value> </KeyValueOfstringanyType> <KeyValueOfstringanyType> <Key>Key3</Key> <Value i:type="a:guid" xmlns:a="http://schemas.microsoft.com/2003/10/Serialization/">2cd46d2a-a636-4af4-979b-e834d39b6d37</Value> </KeyValueOfstringanyType> <KeyValueOfstringanyType> <Key>Key4</Key> <Value i:type="a:dateTime" xmlns:a="http://www.w3.org/2001/XMLSchema">2011-09-19T17:17:05.4406999-07:00</Value> </KeyValueOfstringanyType> <KeyValueOfstringanyType> <Key>Key5</Key> <Value i:type="a:boolean" xmlns:a="http://www.w3.org/2001/XMLSchema">true</Value> </KeyValueOfstringanyType> <KeyValueOfstringanyType> <Key>Key7</Key> <Value i:type="a:base64Binary" xmlns:a="http://www.w3.org/2001/XMLSchema">Ki1C</Value> </KeyValueOfstringanyType> </ArrayOfKeyValueOfstringanyType> Ouch! That seriously hurts the eye! :-) Worse though it's extremely verbose with all those repetitive namespace declarations. It's good to know that it works in a pinch, but for a human readable/editable solution or something lightweight to store in a database it's not quite ideal. Why should I care? As a little background, in one of my applications I have a need for a flexible property bag that is used on a free form database field on an otherwise static entity. Basically what I have is a standard database record to which arbitrary properties can be added in an XML based string field. I intend to expose those arbitrary properties as a collection from field data stored in XML. The concept is pretty simple: When loading write the data to the collection, when the data is saved serialize the data into an XML string and store it into the database. When reading the data pick up the XML and if the collection on the entity is accessed automatically deserialize the XML into the Dictionary. (I'll talk more about this in another post). While the DataContext Serializer would work, it's verbosity is problematic both for size of the generated XML strings and the fact that users can manually edit this XML based property data in an advanced mode. A clean(er) layout certainly would be preferable and more user friendly. Custom XMLSerialization with a PropertyBag Class So… after a bunch of experimentation with different serialization formats I decided to create a custom PropertyBag class that provides for a serializable Dictionary. It's basically a custom Dictionary<TType,TValue> implementation with the keys always set as string keys. The result are PropertyBag<TValue> and PropertyBag (which defaults to the object type for values). The PropertyBag<TType> and PropertyBag classes provide these features: Subclassed from Dictionary<T,V> Implements IXmlSerializable with a cleanish XML format ToXml() and FromXml() methods to export and import to and from XML strings Static CreateFromXml() method to create an instance It's simple enough as it's merely a Dictionary<string,object> subclass but that supports serialization to a - what I think at least - cleaner XML format. The class is super simple to use: [TestMethod] public void PropertyBagTwoWayObjectSerializationTest() { var bag = new PropertyBag(); bag.Add("key", "Value"); bag.Add("Key2", 100.10M); bag.Add("Key3", Guid.NewGuid()); bag.Add("Key4", DateTime.Now); bag.Add("Key5", true); bag.Add("Key7", new byte[3] { 42,45,66 } ); bag.Add("Key8", null); bag.Add("Key9", new ComplexObject() { Name = "Rick", Entered = DateTime.Now, Count = 10 }); string xml = bag.ToXml(); TestContext.WriteLine(bag.ToXml()); bag.Clear(); bag.FromXml(xml); Assert.IsTrue(bag["key"] as string == "Value"); Assert.IsInstanceOfType( bag["Key3"], typeof(Guid)); Assert.IsNull(bag["Key8"]); //Assert.IsNull(bag["Key10"]); Assert.IsInstanceOfType(bag["Key9"], typeof(ComplexObject)); } This uses the PropertyBag class which uses a PropertyBag<string,object> - which means it returns untyped values of type object. I suspect for me this will be the most common scenario as I'd want to store arbitrary values in the PropertyBag rather than one specific type. The same code with a strongly typed PropertyBag<decimal> looks like this: [TestMethod] public void PropertyBagTwoWayValueTypeSerializationTest() { var bag = new PropertyBag<decimal>(); bag.Add("key", 10M); bag.Add("Key1", 100.10M); bag.Add("Key2", 200.10M); bag.Add("Key3", 300.10M); string xml = bag.ToXml(); TestContext.WriteLine(bag.ToXml()); bag.Clear(); bag.FromXml(xml); Assert.IsTrue(bag.Get("Key1") == 100.10M); Assert.IsTrue(bag.Get("Key3") == 300.10M); } and produces typed results of type decimal. The types can be either value or reference types the combination of which actually proved to be a little more tricky than anticipated due to null and specific string value checks required - getting the generic typing right required use of default(T) and Convert.ChangeType() to trick the compiler into playing nice. Of course the whole raison d'etre for this class is the XML serialization. You can see in the code above that we're doing a .ToXml() and .FromXml() to serialize to and from string. The XML produced for the first example looks like this: <?xml version="1.0" encoding="utf-8"?> <properties> <item> <key>key</key> <value>Value</value> </item> <item> <key>Key2</key> <value type="decimal">100.10</value> </item> <item> <key>Key3</key> <value type="___System.Guid"> <guid>f7a92032-0c6d-4e9d-9950-b15ff7cd207d</guid> </value> </item> <item> <key>Key4</key> <value type="datetime">2011-09-26T17:45:58.5789578-10:00</value> </item> <item> <key>Key5</key> <value type="boolean">true</value> </item> <item> <key>Key7</key> <value type="base64Binary">Ki1C</value> </item> <item> <key>Key8</key> <value type="nil" /> </item> <item> <key>Key9</key> <value type="___Westwind.Tools.Tests.PropertyBagTest+ComplexObject"> <ComplexObject> <Name>Rick</Name> <Entered>2011-09-26T17:45:58.5789578-10:00</Entered> <Count>10</Count> </ComplexObject> </value> </item> </properties>   The format is a bit cleaner than the DataContractSerializer. Each item is serialized into <key> <value> pairs. If the value is a string no type information is written. Since string tends to be the most common type this saves space and serialization processing. All other types are attributed. Simple types are mapped to XML types so things like decimal, datetime, boolean and base64Binary are encoded using their Xml type values. All other types are embedded with a hokey format that describes the .NET type preceded by a three underscores and then are encoded using the XmlSerializer. You can see this best above in the ComplexObject encoding. For custom types this isn't pretty either, but it's more concise than the DCS and it works as long as you're serializing back and forth between .NET clients at least. The XML generated from the second example that uses PropertyBag<decimal> looks like this: <?xml version="1.0" encoding="utf-8"?> <properties> <item> <key>key</key> <value type="decimal">10</value> </item> <item> <key>Key1</key> <value type="decimal">100.10</value> </item> <item> <key>Key2</key> <value type="decimal">200.10</value> </item> <item> <key>Key3</key> <value type="decimal">300.10</value> </item> </properties>   How does it work As I mentioned there's nothing fancy about this solution - it's little more than a subclass of Dictionary<T,V> that implements custom Xml Serialization and a couple of helper methods that facilitate getting the XML in and out of the class more easily. But it's proven very handy for a number of projects for me where dynamic data storage is required. Here's the code: /// <summary> /// Creates a serializable string/object dictionary that is XML serializable /// Encodes keys as element names and values as simple values with a type /// attribute that contains an XML type name. Complex names encode the type /// name with type='___namespace.classname' format followed by a standard xml /// serialized format. The latter serialization can be slow so it's not recommended /// to pass complex types if performance is critical. /// </summary> [XmlRoot("properties")] public class PropertyBag : PropertyBag<object> { /// <summary> /// Creates an instance of a propertybag from an Xml string /// </summary> /// <param name="xml">Serialize</param> /// <returns></returns> public static PropertyBag CreateFromXml(string xml) { var bag = new PropertyBag(); bag.FromXml(xml); return bag; } } /// <summary> /// Creates a serializable string for generic types that is XML serializable. /// /// Encodes keys as element names and values as simple values with a type /// attribute that contains an XML type name. Complex names encode the type /// name with type='___namespace.classname' format followed by a standard xml /// serialized format. The latter serialization can be slow so it's not recommended /// to pass complex types if performance is critical. /// </summary> /// <typeparam name="TValue">Must be a reference type. For value types use type object</typeparam> [XmlRoot("properties")] public class PropertyBag<TValue> : Dictionary<string, TValue>, IXmlSerializable { /// <summary> /// Not implemented - this means no schema information is passed /// so this won't work with ASMX/WCF services. /// </summary> /// <returns></returns> public System.Xml.Schema.XmlSchema GetSchema() { return null; } /// <summary> /// Serializes the dictionary to XML. Keys are /// serialized to element names and values as /// element values. An xml type attribute is embedded /// for each serialized element - a .NET type /// element is embedded for each complex type and /// prefixed with three underscores. /// </summary> /// <param name="writer"></param> public void WriteXml(System.Xml.XmlWriter writer) { foreach (string key in this.Keys) { TValue value = this[key]; Type type = null; if (value != null) type = value.GetType(); writer.WriteStartElement("item"); writer.WriteStartElement("key"); writer.WriteString(key as string); writer.WriteEndElement(); writer.WriteStartElement("value"); string xmlType = XmlUtils.MapTypeToXmlType(type); bool isCustom = false; // Type information attribute if not string if (value == null) { writer.WriteAttributeString("type", "nil"); } else if (!string.IsNullOrEmpty(xmlType)) { if (xmlType != "string") { writer.WriteStartAttribute("type"); writer.WriteString(xmlType); writer.WriteEndAttribute(); } } else { isCustom = true; xmlType = "___" + value.GetType().FullName; writer.WriteStartAttribute("type"); writer.WriteString(xmlType); writer.WriteEndAttribute(); } // Actual deserialization if (!isCustom) { if (value != null) writer.WriteValue(value); } else { XmlSerializer ser = new XmlSerializer(value.GetType()); ser.Serialize(writer, value); } writer.WriteEndElement(); // value writer.WriteEndElement(); // item } } /// <summary> /// Reads the custom serialized format /// </summary> /// <param name="reader"></param> public void ReadXml(System.Xml.XmlReader reader) { this.Clear(); while (reader.Read()) { if (reader.NodeType == XmlNodeType.Element && reader.Name == "key") { string xmlType = null; string name = reader.ReadElementContentAsString(); // item element reader.ReadToNextSibling("value"); if (reader.MoveToNextAttribute()) xmlType = reader.Value; reader.MoveToContent(); TValue value; if (xmlType == "nil") value = default(TValue); // null else if (string.IsNullOrEmpty(xmlType)) { // value is a string or object and we can assign TValue to value string strval = reader.ReadElementContentAsString(); value = (TValue) Convert.ChangeType(strval, typeof(TValue)); } else if (xmlType.StartsWith("___")) { while (reader.Read() && reader.NodeType != XmlNodeType.Element) { } Type type = ReflectionUtils.GetTypeFromName(xmlType.Substring(3)); //value = reader.ReadElementContentAs(type,null); XmlSerializer ser = new XmlSerializer(type); value = (TValue)ser.Deserialize(reader); } else value = (TValue)reader.ReadElementContentAs(XmlUtils.MapXmlTypeToType(xmlType), null); this.Add(name, value); } } } /// <summary> /// Serializes this dictionary to an XML string /// </summary> /// <returns>XML String or Null if it fails</returns> public string ToXml() { string xml = null; SerializationUtils.SerializeObject(this, out xml); return xml; } /// <summary> /// Deserializes from an XML string /// </summary> /// <param name="xml"></param> /// <returns>true or false</returns> public bool FromXml(string xml) { this.Clear(); // if xml string is empty we return an empty dictionary if (string.IsNullOrEmpty(xml)) return true; var result = SerializationUtils.DeSerializeObject(xml, this.GetType()) as PropertyBag<TValue>; if (result != null) { foreach (var item in result) { this.Add(item.Key, item.Value); } } else // null is a failure return false; return true; } /// <summary> /// Creates an instance of a propertybag from an Xml string /// </summary> /// <param name="xml"></param> /// <returns></returns> public static PropertyBag<TValue> CreateFromXml(string xml) { var bag = new PropertyBag<TValue>(); bag.FromXml(xml); return bag; } } } The code uses a couple of small helper classes SerializationUtils and XmlUtils for mapping Xml types to and from .NET, both of which are from the WestWind,Utilities project (which is the same project where PropertyBag lives) from the West Wind Web Toolkit. The code implements ReadXml and WriteXml for the IXmlSerializable implementation using old school XmlReaders and XmlWriters (because it's pretty simple stuff - no need for XLinq here). Then there are two helper methods .ToXml() and .FromXml() that basically allow your code to easily convert between XML and a PropertyBag object. In my code that's what I use to actually to persist to and from the entity XML property during .Load() and .Save() operations. It's sweet to be able to have a string key dictionary and then be able to turn around with 1 line of code to persist the whole thing to XML and back. Hopefully some of you will find this class as useful as I've found it. It's a simple solution to a common requirement in my applications and I've used the hell out of it in the  short time since I created it. Resources You can find the complete code for the two classes plus the helpers in the Subversion repository for Westwind.Utilities. You can grab the source files from there or download the whole project. You can also grab the full Westwind.Utilities assembly from NuGet and add it to your project if that's easier for you. PropertyBag Source Code SerializationUtils and XmlUtils Westwind.Utilities Assembly on NuGet (add from Visual Studio) © Rick Strahl, West Wind Technologies, 2005-2011Posted in .NET  CSharp   Tweet (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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• Silverlight Recruiting Application Part 5 - Jobs Module / View

  Now we starting getting into a more code-heavy portion of this series, thankfully though this means the groundwork is all set for the most part and after adding the modules we will have a complete application that can be provided with full source. The Jobs module will have two concerns- adding and maintaining jobs that can then be broadcast out to the website. How they are displayed on the site will be handled by our admin system (which will just poll from this common database), so we aren't too concerned with that, but rather with getting the information into the system and allowing the backend administration/HR users to keep things up to date. Since there is a fair bit of information that we want to display, we're going to move editing to a separate view so we can get all that information in an easy-to-use spot. With all the files created for this module, the project looks something like this: And now... on to the code. XAML for the Job Posting View All we really need for the Job Posting View is a RadGridView and a few buttons. This will let us both show off records and perform operations on the records without much hassle. That XAML is going to look something like this: 01.<Grid x:Name="LayoutRoot" 02.Background="White"> 03.<Grid.RowDefinitions> 04.<RowDefinition Height="30" /> 05.<RowDefinition /> 06.</Grid.RowDefinitions> 07.<StackPanel Orientation="Horizontal"> 08.<Button x:Name="xAddRecordButton" 09.Content="Add Job" 10.Width="120" 11.cal:Click.Command="{Binding AddRecord}" 12.telerik:StyleManager.Theme="Windows7" /> 13.<Button x:Name="xEditRecordButton" 14.Content="Edit Job" 15.Width="120" 16.cal:Click.Command="{Binding EditRecord}" 17.telerik:StyleManager.Theme="Windows7" /> 18.</StackPanel> 19.<telerikGrid:RadGridView x:Name="xJobsGrid" 20.Grid.Row="1" 21.IsReadOnly="True" 22.AutoGenerateColumns="False" 23.ColumnWidth="*" 24.RowDetailsVisibilityMode="VisibleWhenSelected" 25.ItemsSource="{Binding MyJobs}" 26.SelectedItem="{Binding SelectedJob, Mode=TwoWay}" 27.command:SelectedItemChangedEventClass.Command="{Binding SelectedItemChanged}"> 28.<telerikGrid:RadGridView.Columns> 29.<telerikGrid:GridViewDataColumn Header="Job Title" 30.DataMemberBinding="{Binding JobTitle}" 31.UniqueName="JobTitle" /> 32.<telerikGrid:GridViewDataColumn Header="Location" 33.DataMemberBinding="{Binding Location}" 34.UniqueName="Location" /> 35.<telerikGrid:GridViewDataColumn Header="Resume Required" 36.DataMemberBinding="{Binding NeedsResume}" 37.UniqueName="NeedsResume" /> 38.<telerikGrid:GridViewDataColumn Header="CV Required" 39.DataMemberBinding="{Binding NeedsCV}" 40.UniqueName="NeedsCV" /> 41.<telerikGrid:GridViewDataColumn Header="Overview Required" 42.DataMemberBinding="{Binding NeedsOverview}" 43.UniqueName="NeedsOverview" /> 44.<telerikGrid:GridViewDataColumn Header="Active" 45.DataMemberBinding="{Binding IsActive}" 46.UniqueName="IsActive" /> 47.</telerikGrid:RadGridView.Columns> 48.</telerikGrid:RadGridView> 49.</Grid> I'll explain what's happening here by line numbers: Lines 11 and 16: Using the same type of click commands as we saw in the Menu module, we tie the button clicks to delegate commands in the viewmodel. Line 25: The source for the jobs will be a collection in the viewmodel. Line 26: We also bind the selected item to a public property from the viewmodel for use in code. Line 27: We've turned the event into a command so we can handle it via code in the viewmodel. So those first three probably make sense to you as far as Silverlight/WPF binding magic is concerned, but for line 27... This actually comes from something I read onDamien Schenkelman's blog back in the day for creating an attached behavior from any event. So, any time you see me using command:Whatever.Command, the backing for it is actually something like this: SelectedItemChangedEventBehavior.cs: 01.public class SelectedItemChangedEventBehavior : CommandBehaviorBase<Telerik.Windows.Controls.DataControl> 02.{ 03.public SelectedItemChangedEventBehavior(DataControl element) 04.: base(element) 05.{ 06.element.SelectionChanged += new EventHandler<SelectionChangeEventArgs>(element_SelectionChanged); 07.} 08.void element_SelectionChanged(object sender, SelectionChangeEventArgs e) 09.{ 10.// We'll only ever allow single selection, so will only need item index 0 11.base.CommandParameter = e.AddedItems[0]; 12.base.ExecuteCommand(); 13.} 14.} SelectedItemChangedEventClass.cs: 01.public class SelectedItemChangedEventClass 02.{ 03.#region The Command Stuff 04.public static ICommand GetCommand(DependencyObject obj) 05.{ 06.return (ICommand)obj.GetValue(CommandProperty); 07.} 08.public static void SetCommand(DependencyObject obj, ICommand value) 09.{ 10.obj.SetValue(CommandProperty, value); 11.} 12.public static readonly DependencyProperty CommandProperty = 13.DependencyProperty.RegisterAttached("Command", typeof(ICommand), 14.typeof(SelectedItemChangedEventClass), new PropertyMetadata(OnSetCommandCallback)); 15.public static void OnSetCommandCallback(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs e) 16.{ 17.DataControl element = dependencyObject as DataControl; 18.if (element != null) 19.{ 20.SelectedItemChangedEventBehavior behavior = GetOrCreateBehavior(element); 21.behavior.Command = e.NewValue as ICommand; 22.} 23.} 24.#endregion 25.public static SelectedItemChangedEventBehavior GetOrCreateBehavior(DataControl element) 26.{ 27.SelectedItemChangedEventBehavior behavior = element.GetValue(SelectedItemChangedEventBehaviorProperty) as SelectedItemChangedEventBehavior; 28.if (behavior == null) 29.{ 30.behavior = new SelectedItemChangedEventBehavior(element); 31.element.SetValue(SelectedItemChangedEventBehaviorProperty, behavior); 32.} 33.return behavior; 34.} 35.public static SelectedItemChangedEventBehavior GetSelectedItemChangedEventBehavior(DependencyObject obj) 36.{ 37.return (SelectedItemChangedEventBehavior)obj.GetValue(SelectedItemChangedEventBehaviorProperty); 38.} 39.public static void SetSelectedItemChangedEventBehavior(DependencyObject obj, SelectedItemChangedEventBehavior value) 40.{ 41.obj.SetValue(SelectedItemChangedEventBehaviorProperty, value); 42.} 43.public static readonly DependencyProperty SelectedItemChangedEventBehaviorProperty = 44.DependencyProperty.RegisterAttached("SelectedItemChangedEventBehavior", 45.typeof(SelectedItemChangedEventBehavior), typeof(SelectedItemChangedEventClass), null); 46.} These end up looking very similar from command to command, but in a nutshell you create a command based on any event, determine what the parameter for it will be, then execute. It attaches via XAML and ties to a DelegateCommand in the viewmodel, so you get the full event experience (since some controls get a bit event-rich for added functionality). Simple enough, right? Viewmodel for the Job Posting View The Viewmodel is going to need to handle all events going back and forth, maintaining interactions with the data we are using, and both publishing and subscribing to events. Rather than breaking this into tons of little pieces, I'll give you a nice view of the entire viewmodel and then hit up the important points line-by-line: 001.public class JobPostingViewModel : ViewModelBase 002.{ 003.private readonly IEventAggregator eventAggregator; 004.private readonly IRegionManager regionManager; 005.public DelegateCommand<object> AddRecord { get; set; } 006.public DelegateCommand<object> EditRecord { get; set; } 007.public DelegateCommand<object> SelectedItemChanged { get; set; } 008.public RecruitingContext context; 009.private QueryableCollectionView _myJobs; 010.public QueryableCollectionView MyJobs 011.{ 012.get { return _myJobs; } 013.} 014.private QueryableCollectionView _selectionJobActionHistory; 015.public QueryableCollectionView SelectedJobActionHistory 016.{ 017.get { return _selectionJobActionHistory; } 018.} 019.private JobPosting _selectedJob; 020.public JobPosting SelectedJob 021.{ 022.get { return _selectedJob; } 023.set 024.{ 025.if (value != _selectedJob) 026.{ 027._selectedJob = value; 028.NotifyChanged("SelectedJob"); 029.} 030.} 031.} 032.public SubscriptionToken editToken = new SubscriptionToken(); 033.public SubscriptionToken addToken = new SubscriptionToken(); 034.public JobPostingViewModel(IEventAggregator eventAgg, IRegionManager regionmanager) 035.{ 036.// set Unity items 037.this.eventAggregator = eventAgg; 038.this.regionManager = regionmanager; 039.// load our context 040.context = new RecruitingContext(); 041.this._myJobs = new QueryableCollectionView(context.JobPostings); 042.context.Load(context.GetJobPostingsQuery()); 043.// set command events 044.this.AddRecord = new DelegateCommand<object>(this.AddNewRecord); 045.this.EditRecord = new DelegateCommand<object>(this.EditExistingRecord); 046.this.SelectedItemChanged = new DelegateCommand<object>(this.SelectedRecordChanged); 047.SetSubscriptions(); 048.} 049.#region DelegateCommands from View 050.public void AddNewRecord(object obj) 051.{ 052.this.eventAggregator.GetEvent<AddJobEvent>().Publish(true); 053.} 054.public void EditExistingRecord(object obj) 055.{ 056.if (_selectedJob == null) 057.{ 058.this.eventAggregator.GetEvent<NotifyUserEvent>().Publish("No job selected."); 059.} 060.else 061.{ 062.this._myJobs.EditItem(this._selectedJob); 063.this.eventAggregator.GetEvent<EditJobEvent>().Publish(this._selectedJob); 064.} 065.} 066.public void SelectedRecordChanged(object obj) 067.{ 068.if (obj.GetType() == typeof(ActionHistory)) 069.{ 070.// event bubbles up so we don't catch items from the ActionHistory grid 071.} 072.else 073.{ 074.JobPosting job = obj as JobPosting; 075.GrabHistory(job.PostingID); 076.} 077.} 078.#endregion 079.#region Subscription Declaration and Events 080.public void SetSubscriptions() 081.{ 082.EditJobCompleteEvent editComplete = eventAggregator.GetEvent<EditJobCompleteEvent>(); 083.if (editToken != null) 084.editComplete.Unsubscribe(editToken); 085.editToken = editComplete.Subscribe(this.EditCompleteEventHandler); 086.AddJobCompleteEvent addComplete = eventAggregator.GetEvent<AddJobCompleteEvent>(); 087.if (addToken != null) 088.addComplete.Unsubscribe(addToken); 089.addToken = addComplete.Subscribe(this.AddCompleteEventHandler); 090.} 091.public void EditCompleteEventHandler(bool complete) 092.{ 093.if (complete) 094.{ 095.JobPosting thisJob = _myJobs.CurrentEditItem as JobPosting; 096.this._myJobs.CommitEdit(); 097.this.context.SubmitChanges((s) => 098.{ 099.ActionHistory myAction = new ActionHistory(); 100.myAction.PostingID = thisJob.PostingID; 101.myAction.Description = String.Format("Job '{0}' has been edited by {1}", thisJob.JobTitle, "default user"); 102.myAction.TimeStamp = DateTime.Now; 103.eventAggregator.GetEvent<AddActionEvent>().Publish(myAction); 104.} 105., null); 106.} 107.else 108.{ 109.this._myJobs.CancelEdit(); 110.} 111.this.MakeMeActive(this.regionManager, "MainRegion", "JobPostingsView"); 112.} 113.public void AddCompleteEventHandler(JobPosting job) 114.{ 115.if (job == null) 116.{ 117.// do nothing, new job add cancelled 118.} 119.else 120.{ 121.this.context.JobPostings.Add(job); 122.this.context.SubmitChanges((s) => 123.{ 124.ActionHistory myAction = new ActionHistory(); 125.myAction.PostingID = job.PostingID; 126.myAction.Description = String.Format("Job '{0}' has been added by {1}", job.JobTitle, "default user"); 127.myAction.TimeStamp = DateTime.Now; 128.eventAggregator.GetEvent<AddActionEvent>().Publish(myAction); 129.} 130., null); 131.} 132.this.MakeMeActive(this.regionManager, "MainRegion", "JobPostingsView"); 133.} 134.#endregion 135.public void GrabHistory(int postID) 136.{ 137.context.ActionHistories.Clear(); 138._selectionJobActionHistory = new QueryableCollectionView(context.ActionHistories); 139.context.Load(context.GetHistoryForJobQuery(postID)); 140.} Taking it from the top, we're injecting an Event Aggregator and Region Manager for use down the road and also have the public DelegateCommands (just like in the Menu module). We also grab a reference to our context, which we'll obviously need for data, then set up a few fields with public properties tied to them. We're also setting subscription tokens, which we have not yet seen but I will get into below. The AddNewRecord (50) and EditExistingRecord (54) methods should speak for themselves for functionality, the one thing of note is we're sending events off to the Event Aggregator which some module, somewhere will take care of. Since these aren't entirely relying on one another, the Jobs View doesn't care if anyone is listening, but it will publish AddJobEvent (52), NotifyUserEvent (58) and EditJobEvent (63)regardless. Don't mind the GrabHistory() method so much, that is just grabbing history items (visibly being created in the SubmitChanges callbacks), and adding them to the database. Every action will trigger a history event, so we'll know who modified what and when, just in case. ;) So where are we at? Well, if we click to Add a job, we publish an event, if we edit a job, we publish an event with the selected record (attained through the magic of binding). Where is this all going though? To the Viewmodel, of course! XAML for the AddEditJobView This is pretty straightforward except for one thing, noted below: 001.<Grid x:Name="LayoutRoot" 002.Background="White"> 003.<Grid x:Name="xEditGrid" 004.Margin="10" 005.validationHelper:ValidationScope.Errors="{Binding Errors}"> 006.<Grid.Background> 007.<LinearGradientBrush EndPoint="0.5,1" 008.StartPoint="0.5,0"> 009.<GradientStop Color="#FFC7C7C7" 010.Offset="0" /> 011.<GradientStop Color="#FFF6F3F3" 012.Offset="1" /> 013.</LinearGradientBrush> 014.</Grid.Background> 015.<Grid.RowDefinitions> 016.<RowDefinition Height="40" /> 017.<RowDefinition Height="40" /> 018.<RowDefinition Height="40" /> 019.<RowDefinition Height="100" /> 020.<RowDefinition Height="100" /> 021.<RowDefinition Height="100" /> 022.<RowDefinition Height="40" /> 023.<RowDefinition Height="40" /> 024.<RowDefinition Height="40" /> 025.</Grid.RowDefinitions> 026.<Grid.ColumnDefinitions> 027.<ColumnDefinition Width="150" /> 028.<ColumnDefinition Width="150" /> 029.<ColumnDefinition Width="300" /> 030.<ColumnDefinition Width="100" /> 031.</Grid.ColumnDefinitions> 032.<!-- Title --> 033.<TextBlock Margin="8" 034.Text="{Binding AddEditString}" 035.TextWrapping="Wrap" 036.Grid.Column="1" 037.Grid.ColumnSpan="2" 038.FontSize="16" /> 039.<!-- Data entry area--> 040. 041.<TextBlock Margin="8,0,0,0" 042.Style="{StaticResource LabelTxb}" 043.Grid.Row="1" 044.Text="Job Title" 045.VerticalAlignment="Center" /> 046.<TextBox x:Name="xJobTitleTB" 047.Margin="0,8" 048.Grid.Column="1" 049.Grid.Row="1" 050.Text="{Binding activeJob.JobTitle, Mode=TwoWay, NotifyOnValidationError=True, ValidatesOnExceptions=True}" 051.Grid.ColumnSpan="2" /> 052.<TextBlock Margin="8,0,0,0" 053.Grid.Row="2" 054.Text="Location" 055.d:LayoutOverrides="Height" 056.VerticalAlignment="Center" /> 057.<TextBox x:Name="xLocationTB" 058.Margin="0,8" 059.Grid.Column="1" 060.Grid.Row="2" 061.Text="{Binding activeJob.Location, Mode=TwoWay, NotifyOnValidationError=True, ValidatesOnExceptions=True}" 062.Grid.ColumnSpan="2" /> 063. 064.<TextBlock Margin="8,11,8,0" 065.Grid.Row="3" 066.Text="Description" 067.TextWrapping="Wrap" 068.VerticalAlignment="Top" /> 069. 070.<TextBox x:Name="xDescriptionTB" 071.Height="84" 072.TextWrapping="Wrap" 073.ScrollViewer.VerticalScrollBarVisibility="Auto" 074.Grid.Column="1" 075.Grid.Row="3" 076.Text="{Binding activeJob.Description, Mode=TwoWay, NotifyOnValidationError=True, ValidatesOnExceptions=True}" 077.Grid.ColumnSpan="2" /> 078.<TextBlock Margin="8,11,8,0" 079.Grid.Row="4" 080.Text="Requirements" 081.TextWrapping="Wrap" 082.VerticalAlignment="Top" /> 083. 084.<TextBox x:Name="xRequirementsTB" 085.Height="84" 086.TextWrapping="Wrap" 087.ScrollViewer.VerticalScrollBarVisibility="Auto" 088.Grid.Column="1" 089.Grid.Row="4" 090.Text="{Binding activeJob.Requirements, Mode=TwoWay, NotifyOnValidationError=True, ValidatesOnExceptions=True}" 091.Grid.ColumnSpan="2" /> 092.<TextBlock Margin="8,11,8,0" 093.Grid.Row="5" 094.Text="Qualifications" 095.TextWrapping="Wrap" 096.VerticalAlignment="Top" /> 097. 098.<TextBox x:Name="xQualificationsTB" 099.Height="84" 100.TextWrapping="Wrap" 101.ScrollViewer.VerticalScrollBarVisibility="Auto" 102.Grid.Column="1" 103.Grid.Row="5" 104.Text="{Binding activeJob.Qualifications, Mode=TwoWay, NotifyOnValidationError=True, ValidatesOnExceptions=True}" 105.Grid.ColumnSpan="2" /> 106.<!-- Requirements Checkboxes--> 107. 108.<CheckBox x:Name="xResumeRequiredCB" Margin="8,8,8,15" 109.Content="Resume Required" 110.Grid.Row="6" 111.Grid.ColumnSpan="2" 112.IsChecked="{Binding activeJob.NeedsResume, Mode=TwoWay, NotifyOnValidationError=True, ValidatesOnExceptions=True}"/> 113. 114.<CheckBox x:Name="xCoverletterRequiredCB" Margin="8,8,8,15" 115.Content="Cover Letter Required" 116.Grid.Column="2" 117.Grid.Row="6" 118.IsChecked="{Binding activeJob.NeedsCV, Mode=TwoWay, NotifyOnValidationError=True, ValidatesOnExceptions=True}"/> 119. 120.<CheckBox x:Name="xOverviewRequiredCB" Margin="8,8,8,15" 121.Content="Overview Required" 122.Grid.Row="7" 123.Grid.ColumnSpan="2" 124.IsChecked="{Binding activeJob.NeedsOverview, Mode=TwoWay, NotifyOnValidationError=True, ValidatesOnExceptions=True}"/> 125. 126.<CheckBox x:Name="xJobActiveCB" Margin="8,8,8,15" 127.Content="Job is Active" 128.Grid.Column="2" 129.Grid.Row="7" 130.IsChecked="{Binding activeJob.IsActive, Mode=TwoWay, NotifyOnValidationError=True, ValidatesOnExceptions=True}"/> 131. 132.<!-- Buttons --> 133. 134.<Button x:Name="xAddEditButton" Margin="8,8,0,10" 135.Content="{Binding AddEditButtonString}" 136.cal:Click.Command="{Binding AddEditCommand}" 137.Grid.Column="2" 138.Grid.Row="8" 139.HorizontalAlignment="Left" 140.Width="125" 141.telerik:StyleManager.Theme="Windows7" /> 142. 143.<Button x:Name="xCancelButton" HorizontalAlignment="Right" 144.Content="Cancel" 145.cal:Click.Command="{Binding CancelCommand}" 146.Margin="0,8,8,10" 147.Width="125" 148.Grid.Column="2" 149.Grid.Row="8" 150.telerik:StyleManager.Theme="Windows7" /> 151.</Grid> 152.</Grid> The 'validationHelper:ValidationScope' line may seem odd. This is a handy little trick for catching current and would-be validation errors when working in this whole setup. This all comes from an approach found on theJoy Of Code blog, although it looks like the story for this will be changing slightly with new advances in SL4/WCF RIA Services, so this section can definitely get an overhaul a little down the road. The code is the fun part of all this, so let us see what's happening under the hood. Viewmodel for the AddEditJobView We are going to see some of the same things happening here, so I'll skip over the repeat info and get right to the good stuff: 001.public class AddEditJobViewModel : ViewModelBase 002.{ 003.private readonly IEventAggregator eventAggregator; 004.private readonly IRegionManager regionManager; 005. 006.public RecruitingContext context; 007. 008.private JobPosting _activeJob; 009.public JobPosting activeJob 010.{ 011.get { return _activeJob; } 012.set 013.{ 014.if (_activeJob != value) 015.{ 016._activeJob = value; 017.NotifyChanged("activeJob"); 018.} 019.} 020.} 021. 022.public bool isNewJob; 023. 024.private string _addEditString; 025.public string AddEditString 026.{ 027.get { return _addEditString; } 028.set 029.{ 030.if (_addEditString != value) 031.{ 032._addEditString = value; 033.NotifyChanged("AddEditString"); 034.} 035.} 036.} 037. 038.private string _addEditButtonString; 039.public string AddEditButtonString 040.{ 041.get { return _addEditButtonString; } 042.set 043.{ 044.if (_addEditButtonString != value) 045.{ 046._addEditButtonString = value; 047.NotifyChanged("AddEditButtonString"); 048.} 049.} 050.} 051. 052.public SubscriptionToken addJobToken = new SubscriptionToken(); 053.public SubscriptionToken editJobToken = new SubscriptionToken(); 054. 055.public DelegateCommand<object> AddEditCommand { get; set; } 056.public DelegateCommand<object> CancelCommand { get; set; } 057. 058.private ObservableCollection<ValidationError> _errors = new ObservableCollection<ValidationError>(); 059.public ObservableCollection<ValidationError> Errors 060.{ 061.get { return _errors; } 062.} 063. 064.private ObservableCollection<ValidationResult> _valResults = new ObservableCollection<ValidationResult>(); 065.public ObservableCollection<ValidationResult> ValResults 066.{ 067.get { return this._valResults; } 068.} 069. 070.public AddEditJobViewModel(IEventAggregator eventAgg, IRegionManager regionmanager) 071.{ 072.// set Unity items 073.this.eventAggregator = eventAgg; 074.this.regionManager = regionmanager; 075. 076.context = new RecruitingContext(); 077. 078.AddEditCommand = new DelegateCommand<object>(this.AddEditJobCommand); 079.CancelCommand = new DelegateCommand<object>(this.CancelAddEditCommand); 080. 081.SetSubscriptions(); 082.} 083. 084.#region Subscription Declaration and Events 085. 086.public void SetSubscriptions() 087.{ 088.AddJobEvent addJob = this.eventAggregator.GetEvent<AddJobEvent>(); 089. 090.if (addJobToken != null) 091.addJob.Unsubscribe(addJobToken); 092. 093.addJobToken = addJob.Subscribe(this.AddJobEventHandler); 094. 095.EditJobEvent editJob = this.eventAggregator.GetEvent<EditJobEvent>(); 096. 097.if (editJobToken != null) 098.editJob.Unsubscribe(editJobToken); 099. 100.editJobToken = editJob.Subscribe(this.EditJobEventHandler); 101.} 102. 103.public void AddJobEventHandler(bool isNew) 104.{ 105.this.activeJob = null; 106.this.activeJob = new JobPosting(); 107.this.activeJob.IsActive = true; // We assume that we want a new job to go up immediately 108.this.isNewJob = true; 109.this.AddEditString = "Add New Job Posting"; 110.this.AddEditButtonString = "Add Job"; 111. 112.MakeMeActive(this.regionManager, "MainRegion", "AddEditJobView"); 113.} 114. 115.public void EditJobEventHandler(JobPosting editJob) 116.{ 117.this.activeJob = null; 118.this.activeJob = editJob; 119.this.isNewJob = false; 120.this.AddEditString = "Edit Job Posting"; 121.this.AddEditButtonString = "Edit Job"; 122. 123.MakeMeActive(this.regionManager, "MainRegion", "AddEditJobView"); 124.} 125. 126.#endregion 127. 128.#region DelegateCommands from View 129. 130.public void AddEditJobCommand(object obj) 131.{ 132.if (this.Errors.Count > 0) 133.{ 134.List<string> errorMessages = new List<string>(); 135. 136.foreach (var valR in this.Errors) 137.{ 138.errorMessages.Add(valR.Exception.Message); 139.} 140. 141.this.eventAggregator.GetEvent<DisplayValidationErrorsEvent>().Publish(errorMessages); 142. 143.} 144.else if (!Validator.TryValidateObject(this.activeJob, new ValidationContext(this.activeJob, null, null), _valResults, true)) 145.{ 146.List<string> errorMessages = new List<string>(); 147. 148.foreach (var valR in this._valResults) 149.{ 150.errorMessages.Add(valR.ErrorMessage); 151.} 152. 153.this._valResults.Clear(); 154. 155.this.eventAggregator.GetEvent<DisplayValidationErrorsEvent>().Publish(errorMessages); 156.} 157.else 158.{ 159.if (this.isNewJob) 160.{ 161.this.eventAggregator.GetEvent<AddJobCompleteEvent>().Publish(this.activeJob); 162.} 163.else 164.{ 165.this.eventAggregator.GetEvent<EditJobCompleteEvent>().Publish(true); 166.} 167.} 168.} 169. 170.public void CancelAddEditCommand(object obj) 171.{ 172.if (this.isNewJob) 173.{ 174.this.eventAggregator.GetEvent<AddJobCompleteEvent>().Publish(null); 175.} 176.else 177.{ 178.this.eventAggregator.GetEvent<EditJobCompleteEvent>().Publish(false); 179.} 180.} 181. 182.#endregion 183.} 184.} We start seeing something new on line 103- the AddJobEventHandler will create a new job and set that to the activeJob item on the ViewModel. When this is all set, the view calls that familiar MakeMeActive method to activate itself. I made a bit of a management call on making views self-activate like this, but I figured it works for one reason. As I create this application, views may not exist that I have in mind, so after a view receives its 'ping' from being subscribed to an event, it prepares whatever it needs to do and then goes active. This way if I don't have 'edit' hooked up, I can click as the day is long on the main view and won't get lost in an empty region. Total personal preference here. :) Everything else should again be pretty straightforward, although I do a bit of validation checking in the AddEditJobCommand, which can either fire off an event back to the main view/viewmodel if everything is a success or sent a list of errors to our notification module, which pops open a RadWindow with the alerts if any exist. As a bonus side note, here's what my WCF RIA Services metadata looks like for handling all of the validation: private JobPostingMetadata() { } [StringLength(2500, ErrorMessage = "Description should be more than one and less than 2500 characters.", MinimumLength = 1)] [Required(ErrorMessage = "Description is required.")] public string Description; [Required(ErrorMessage="Active Status is Required")] public bool IsActive; [StringLength(100, ErrorMessage = "Posting title must be more than 3 but less than 100 characters.", MinimumLength = 3)] [Required(ErrorMessage = "Job Title is required.")] public bool JobTitle; [Required] public string Location; public bool NeedsCV; public bool NeedsOverview; public bool NeedsResume; public int PostingID; [Required(ErrorMessage="Qualifications are required.")] [StringLength(2500, ErrorMessage="Qualifications should be more than one and less than 2500 characters.", MinimumLength=1)] public string Qualifications; [StringLength(2500, ErrorMessage = "Requirements should be more than one and less than 2500 characters.", MinimumLength = 1)] [Required(ErrorMessage="Requirements are required.")] public string Requirements;   The RecruitCB Alternative See all that Xaml I pasted above? Those are now two pieces sitting in the JobsView.xaml file now. The only real difference is that the xEditGrid now sits in the same place as xJobsGrid, with visibility swapping out between the two for a quick switch. I also took out all the cal: and command: command references and replaced Button events with clicks and the Grid selection command replaced with a SelectedItemChanged event. Also, at the bottom of the xEditGrid after the last button, I add a ValidationSummary (with Visibility=Collapsed) to catch any errors that are popping up. Simple as can be, and leads to this being the single code-behind file: 001.public partial class JobsView : UserControl 002.{ 003.public RecruitingContext context; 004.public JobPosting activeJob; 005.public bool isNew; 006.private ObservableCollection<ValidationResult> _valResults = new ObservableCollection<ValidationResult>(); 007.public ObservableCollection<ValidationResult> ValResults 008.{ 009.get { return this._valResults; } 010.} 011.public JobsView() 012.{ 013.InitializeComponent(); 014.this.Loaded += new RoutedEventHandler(JobsView_Loaded); 015.} 016.void JobsView_Loaded(object sender, RoutedEventArgs e) 017.{ 018.context = new RecruitingContext(); 019.xJobsGrid.ItemsSource = context.JobPostings; 020.context.Load(context.GetJobPostingsQuery()); 021.} 022.private void xAddRecordButton_Click(object sender, RoutedEventArgs e) 023.{ 024.activeJob = new JobPosting(); 025.isNew = true; 026.xAddEditTitle.Text = "Add a Job Posting"; 027.xAddEditButton.Content = "Add"; 028.xEditGrid.DataContext = activeJob; 029.HideJobsGrid(); 030.} 031.private void xEditRecordButton_Click(object sender, RoutedEventArgs e) 032.{ 033.activeJob = xJobsGrid.SelectedItem as JobPosting; 034.isNew = false; 035.xAddEditTitle.Text = "Edit a Job Posting"; 036.xAddEditButton.Content = "Edit"; 037.xEditGrid.DataContext = activeJob; 038.HideJobsGrid(); 039.} 040.private void xAddEditButton_Click(object sender, RoutedEventArgs e) 041.{ 042.if (!Validator.TryValidateObject(this.activeJob, new ValidationContext(this.activeJob, null, null), _valResults, true)) 043.{ 044.List<string> errorMessages = new List<string>(); 045.foreach (var valR in this._valResults) 046.{ 047.errorMessages.Add(valR.ErrorMessage); 048.} 049.this._valResults.Clear(); 050.ShowErrors(errorMessages); 051.} 052.else if (xSummary.Errors.Count > 0) 053.{ 054.List<string> errorMessages = new List<string>(); 055.foreach (var err in xSummary.Errors) 056.{ 057.errorMessages.Add(err.Message); 058.} 059.ShowErrors(errorMessages); 060.} 061.else 062.{ 063.if (this.isNew) 064.{ 065.context.JobPostings.Add(activeJob); 066.context.SubmitChanges((s) => 067.{ 068.ActionHistory thisAction = new ActionHistory(); 069.thisAction.PostingID = activeJob.PostingID; 070.thisAction.Description = String.Format("Job '{0}' has been edited by {1}", activeJob.JobTitle, "default user"); 071.thisAction.TimeStamp = DateTime.Now; 072.context.ActionHistories.Add(thisAction); 073.context.SubmitChanges(); 074.}, null); 075.} 076.else 077.{ 078.context.SubmitChanges((s) => 079.{ 080.ActionHistory thisAction = new ActionHistory(); 081.thisAction.PostingID = activeJob.PostingID; 082.thisAction.Description = String.Format("Job '{0}' has been added by {1}", activeJob.JobTitle, "default user"); 083.thisAction.TimeStamp = DateTime.Now; 084.context.ActionHistories.Add(thisAction); 085.context.SubmitChanges(); 086.}, null); 087.} 088.ShowJobsGrid(); 089.} 090.} 091.private void xCancelButton_Click(object sender, RoutedEventArgs e) 092.{ 093.ShowJobsGrid(); 094.} 095.private void ShowJobsGrid() 096.{ 097.xAddEditRecordButtonPanel.Visibility = Visibility.Visible; 098.xEditGrid.Visibility = Visibility.Collapsed; 099.xJobsGrid.Visibility = Visibility.Visible; 100.} 101.private void HideJobsGrid() 102.{ 103.xAddEditRecordButtonPanel.Visibility = Visibility.Collapsed; 104.xJobsGrid.Visibility = Visibility.Collapsed; 105.xEditGrid.Visibility = Visibility.Visible; 106.} 107.private void ShowErrors(List<string> errorList) 108.{ 109.string nm = "Errors received: \n"; 110.foreach (string anerror in errorList) 111.nm += anerror + "\n"; 112.RadWindow.Alert(nm); 113.} 114.} The first 39 lines should be pretty familiar, not doing anything too unorthodox to get this up and running. Once we hit the xAddEditButton_Click on line 40, we're still doing pretty much the same things except instead of checking the ValidationHelper errors, we both run a check on the current activeJob object as well as check the ValidationSummary errors list. Once that is set, we again use the callback of context.SubmitChanges (lines 68 and 78) to create an ActionHistory which we will use to track these items down the line. That's all? Essentially... yes. If you look back through this post, most of the code and adventures we have taken were just to get things working in the MVVM/Prism setup. Since I have the whole 'module' self-contained in a single JobView+code-behind setup, I don't have to worry about things like sending events off into space for someone to pick up, communicating through an Infrastructure project, or even re-inventing events to be used with attached behaviors. Everything just kinda works, and again with much less code. Here's a picture of the MVVM and Code-behind versions on the Jobs and AddEdit views, but since the functionality is the same in both apps you still cannot tell them apart (for two-strike): Looking ahead, the Applicants module is effectively the same thing as the Jobs module, so most of the code is being cut-and-pasted back and forth with minor tweaks here and there. So that one is being taken care of by me behind the scenes. Next time, we get into a new world of fun- the interview scheduling module, which will pull from available jobs and applicants for each interview being scheduled, tying everything together with RadScheduler to the rescue. Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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