Search Results

Search found 4893 results on 196 pages for 'expect'.

Page 181/196 | < Previous Page | 177 178 179 180 181 182 183 184 185 186 187 188  | Next Page >

• ODBC: when is the best time to create my database?

  - by mawg

  I have a windows program which generates PGP forms which will be filled in later. Those PHP forms will populate a database. It looks very much like MySql, but I can't be certain, so let's call it ODBC. And, yes, it does have to be a windows program. There will also be PHP forms which query the database - examine which tables and fields it contains and then generates forms which can be used to search the database (e.g, it finds a table with fields "employee_name", etc and generates a form which lets you search based on employee name. Let's call that design time and run time. At design time, some manager or IT guy or similar gets to define the nature of the database and at runtime 1) a worker fills in the form daily and 2) management can extract reports. Here's my question: given that the database is defined at "design time" (and populated at run time), where and how is best to do so? 1 I could use an ODBC interface from the windows program, but I am having difficulty finding something good to work with Delphi. Things like ADO and firebird tend to expect you to already have a database and allow you to manipulate it, but I can find no code example of how to create a database and some tables, so ... 2 I could used DOS commands from Delphi in my windows program. I just tried and got a response to MySql --version, but am not sure if MySql etc are more interactive. That is, can I use a script file or a very long stacked command with semicolons and returns separating? e.g 'CREATE DATABASE db; CREATE TABLE t1;' 3) Since the best way to work with databases seems to be PHP, perhaps my windows program could spit out a PHP page which would, when run in a browser, create the database. I have tried to make this as uncomplicated as I can, but please feel free to ask questions. It may be that there are several valid ways, but there is probably one 'better' solution in terms of ease of implementation or maintenance. Better scratch option 3. What if the user later wants to come back and have the windows program change the input form? It needs to update the database too.

  Read the article

• Can't get jQuery to get focus on cloned input fields

  - by Rebel1Moon

  I have a page that needs to create dynamic form fields as often as the user needs, and I am trying to use Ajax to tie it in to my database for faster form entry and to prevent user typos. So, I have put my Ajax returned data into popup div, the user selects, then the form field is filled in. The problem comes on the cloned fields. They don't seem to want to bring up the popup div when focused. I am thinking it is something to do with when they get created/added to the DOM. Here is my JS that creates the clones: $(document).ready(function() { var regex = /^(.*)(\d)+$/i; var cloneIndex = $(".clonedInput").length; $("button.clone").live("click", function(){ $(this).parents(".clonedInput").clone() .appendTo("#course_container") .attr("id", "clonedInput" + cloneIndex) .find("*").each(function() { var id = this.id || ""; var match = id.match(regex) || []; if (match.length == 3) { this.id = match[1] + (cloneIndex); } }); cloneIndex++; numClones=cloneIndex-1; //alert("numClones "+numClones); }); Here is where I expect to be able to get focus on the correct cloned field and call the popup. The baker_equiv0 id is original code, whereas baker_equiv1 is the first clone. $('#baker_equiv0').focus(function() { \\ THIS CODE WORKS $('.popup').fadeIn(500); $('#results').empty(); // document.enter_data.baker_equiv1.value="test"; THIS LINE WORKS //alert("numClones "+numClones); }); $('#baker_equiv1').focus(function() { // THIS DOESN'T EVER FIRE alert("numClones "+numClones); $('.popup').fadeIn(500); $('#results').empty(); }); Here is the HTML with the form: <label for="baker_equiv" class="">Baker Equivalent: <span class="requiredField">*</span></label> <input type="text" class="cinputsa" name="baker_equiv[]" id="baker_equiv0" size="8" ONKEYUP="get_equiv(this.value);"> If I put this in the HTML code above, it works fine: onfocus="alert(this.id)" I'd also be interested in how to adjust the JS code to work based on the id array created rather than having to copy code for each potential set of fields clones, i.e., baker_equiv[] rather than baker_equiv0, baker_equiv1, etc. Thanks all!

  Read the article

• Painted JPanel won't show up in JFrame

  - by javawarrior

  When I run my code, I expect to see a JPanel in my JFrame, but nothing shows up. I had a button in the frame, and it shows up. But the JPanel doesn't show up, I even colored it in red. Here is the code for my JPanel: import java.awt.*; import javax.swing.JPanel; public class graphic extends JPanel { private static final long serialVersionUID = -3458717449092499931L; public Game game; public graphic(Game game){ this.game = game; this.setPreferredSize(new Dimension(400,400)); this.setBackground(Color.RED); } public void paintComponent(Graphics g){ for (Line l:game.mirrors){ g.setColor(Color.BLACK); g.drawLine(l.start.x, l.start.y, l.end.x, l.end.y); } } } And my JFrame code: import java.awt.Container; import java.awt.event.*; import java.util.Timer; import java.util.TimerTask; import javax.swing.*; public class Viewer implements ActionListener { public JFrame frame; public JButton drawShoot; public boolean draw; public Game game; public graphic graphic; public TimerTask timert; public Timer timer; public Viewer(){ draw = true; game = new Game(); } public static void main(String args[]){ Viewer v = new Viewer(); v.setup(); } public void setup(){ frame = new JFrame("Laser Stimulator"); drawShoot = new JButton("Edit Mode"); graphic = new graphic(game); graphic.repaint(); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setBounds(300, 300, 600, 600); Container contentPane = frame.getContentPane(); SpringLayout layout = new SpringLayout(); contentPane.setLayout(layout); drawShoot.addActionListener(this); timert = new TimerTask() { @Override public void run() { } }; timer =new Timer(); timer.scheduleAtFixedRate(timert, 0, 1000/30); contentPane.add(graphic); layout.putConstraint(SpringLayout.NORTH, graphic, 0, SpringLayout.NORTH, contentPane); layout.putConstraint(SpringLayout.WEST, graphic, 0, SpringLayout.WEST, contentPane); frame.setVisible(true); } @Override public void actionPerformed(ActionEvent e) { if (e.getSource()==drawShoot){ draw = !draw; drawShoot.setText((draw)?"Edit Mode":"Shoot Mode"); } } }

  Read the article

• Mixing C and C++, raw pointers and (boost) shared pointers

  - by oompahloompah

  I am working in C++ with some legacy C code. I have a data structure that (during initialisation), makes a copy of the structure pointed to a ptr passed to its initialisation pointer. Here is a simplification of what I am trying to do - hopefully, no important detail has been lost in the "simplification": /* C code */ typedef struct MyData { double * elems; unsigned int len; }; int NEW_mydata(MyData* data, unsigned int len) { // no error checking data->elems = (double *)calloc(len, sizeof(double)); return 0; } typedef struct Foo { MyData data data_; }; void InitFoo(Foo * foo, const MyData * the_data) { //alloc mem etc ... then assign the STRUCTURE foo.data_ = *thedata ; } C++ code ------------- typedef boost::shared_ptr<MyData> MyDataPtr; typedef std::map<std::string, MyDataPtr> Datamap; class FooWrapper { public: FooWrapper(const std::string& key) { MyDataPtr mdp = dmap[key]; InitFoo(&m_foo, const_cast<MyData*>((*mdp.get()))); } ~FooWrapper(); double get_element(unsigned int index ) const { return m_foo.elems[index]; } private: // non copyable, non-assignable FooWrapper(const FooWrapper&); FooWrapper& operator= (const FooWrapper&); Foo m_foo; }; int main(int argc, char *argv[]) { MyData data1, data2; Datamap dmap; NEW_mydata(&data1, 10); data1->elems[0] = static_cast<double>(22/7); NEW_mydata(&data2, 42); data2->elems[0] = static_cast<double>(13/21); boost::shared_ptr d1(&data1), d2(&data2); dmap["data1"] = d1; dmap["data2"] = d2; FooWrapper fw("data1"); //expect 22/7, get something else (random number?) double ret fw.get_element(0); } Essentially, what I want to know is this: Is there any reason why the data retrieved from the map is different from the one stored in the map?

  Read the article

• How to pass a variable inside a jquery fonction $.each($("abc")...?

  - by Rock

  I'm trying to iterate a bunch of SELECT OPTION html drop-down fields and from the ones that are NOT empty, take the values and add a hidden field for a PAYPAL shopping cart. My problem is that for some reason, the variable "curitem" is not passed inside the each function and I can't add the hidden field like they should. All I get is "NaN" or "undefined". What PAYPAL expect is : item_name_1, item_name_2, etc. All numbers must iterate by +1. How can I do this? Thanks a bunch in advance var curitem; $.each($("select"), function(index, item) { var attname = $(this).attr("name"); var nom = $(this).attr("data-nom"); var prix = $(this).attr("data-val"); var partname = attname.substring(0, 1); var qte = $(this).val(); // i want all my <select option> items that the NAME start with "q" AND have a value selected if (partname == "q" && isNaN(qte) == false && qte > 0) { // item name var inp2 = document.createElement("input"); inp2.setAttribute("type", "hidden"); inp2.setAttribute("id", "item_name_"+curitem); inp2.setAttribute("name", "item_name_"+curitem); inp2.setAttribute("value", nom); // amount var inp3 = document.createElement("input"); inp3.setAttribute("type", "hidden"); inp3.setAttribute("id", "amount_"+curitem); inp3.setAttribute("name", "amount_"+curitem); inp3.setAttribute("value", prix); // qty var inp4 = document.createElement("input"); inp4.setAttribute("type", "hidden"); inp4.setAttribute("id", "quantity_"+curitem); inp4.setAttribute("name", "quantity_"+curitem); inp4.setAttribute("value", qte); // add hidden fields to form document.getElementById('payPalForm').appendChild(inp2); document.getElementById('payPalForm').appendChild(inp3); document.getElementById('payPalForm').appendChild(inp4); // item number curitem = curitem + 1; } });

  Read the article

• What are the Rails best practices for javascript templates in restful/resourceful controllers?

  - by numbers1311407

  First, 2 common (basic) approaches: # returning from some FoosController method respond_to do |format| # 1. render the javascript directly format.js { render :json => @foo.to_json } # 2. render the default template, say update.js.erb format.js { render } end # in update.js.erb $('#foo').html("<%= escape_javascript(render(@foo)) %>") These are obviously simple cases but I wanted to illustrate what I'm talking about. I believe that these are also the cases expected by the default responder in rails 3 (either the action-named default template or calling to_#{format} on the resource.) The Issues With 1, you have total flexibility on the view side with no worries about the template, but you have to manipulate the DOM directly via javascript. You lose access to helpers, partials, etc. With 2, you have partials and helpers at your disposal, but you're tied to the one template (by default at least). All your views that make JS calls to FoosController use the same template, which isn't exactly flexible. Three Other Approaches (none really satisfactory) 1.) Escape partials/helpers I need into javascript beforehand, then inserting them into the page after, using string replacement to tailor them to the results returned (subbing in name, id, etc). 2.) Put view logic in the templates. For example, looking for a particular DOM element and doing one thing if it exists, another if it does not. 3.) Put logic in the controller to render different templates. For example, in a polymorphic belongs to where update might be called for either comments/foo or posts/foo, rendering commnts/foos/update.js.erb versus posts/foos/update.js.erb. I've used all of these (and probably others I'm not thinking of). Often in the same app, which leads to confusing code. Are there best practices for this sort of thing? It seems like a common enough use-case that you'd want to call controllers via Ajax actions from different views and expect different things to happen (without having to do tedious things like escaping and string-replacing partials and helpers client side). Any thoughts?

  Read the article

• Binary Search Tree Contains Function

  - by Suede

  I am trying to write a "contains" function for a binary search tree. I receive the following error at compile "Unhandled exception at 0x77291CB3 (ntdll.dll) in BST.exe: 0xC00000FD: Stack overflow (parameters: 0x00000001, 0x001E2FFC)." The following is my code. struct Node { int data; Node* leftChild; Node* rightChild; Node() : leftChild(NULL), rightChild(NULL) {} }; struct BST { Node* root; BST() : root(NULL) {} void insert(int value); bool contains(int value); }; void BST::insert(int value) { Node* temp = new Node(); temp->data = value; if(root == NULL) { root = temp; return; } Node* current; current = root; Node* parent; parent = root; current = (temp->data < current->data ? (current->leftChild) : (current->rightChild) while(current != NULL) { parent = current; current = (temp->data < current->data) ? (current->leftChild) : (current->rightChild) } if(temp->data < parent->data) { parent->leftChild = temp; } if(temp->data > parent->data) { parent->rightChild = temp; } } bool BST::contains(int value) { Node* temp = new Node(); temp->data = value; Node* current; current = root; if(temp->data == current->data) { // base case for when node with value is found std::cout << "true" << std::endl; return true; } if(current == NULL) { // base case if BST is empty or if a leaf is reached before value is found std::cout << "false" << std::endl; return false; } else { // recursive step current = (temp->data < current->data) ? (current->leftChild) : (current->rightChild); return contains(temp->data); } } int main() { BST bst; bst.insert(5); bst.contains(4); system("pause"); } As it stands, I would insert a single node with value '5' and I would search the binary search tree for a node with value '4' - thus, I would expect the result to be false.

  Read the article

• PHP Forms checkbox calculation

  - by Sef

  Hello, I am trying to perform some calculations with a form but every time i try to work with checkboxes it goes wrong. The checkboxes are beign set on value 1 in the form itselff and are being checked if there checked or not. $verdieping = isset($_POST["verdieping"]) ? $_POST["verdieping"] : 0; $telefoon = isset($_POST["telefoon"]) ? $_POST["telefoon"] : 0; $netwerk = isset($_POST["netwerk"]) ? $_POST["netwerk"] : 0; When i try to do calculations every works expect for the options with the checkboxes. When both checkboxes (telefoon & netwerk) are selected the value should be 30. If only one is selected the value should be 20. But no mather what i have tried to write down it always give problem, and it always uses 20, never the value 30. How do i solve this problem? Or suppose i am writing the syntax all wrong to lay conditions to a calculation? Any input appreciated. $standnaam = $_SESSION["standnaam"]; $oppervlakte = $_SESSION["oppervlakte"]; $verdieping = $_SESSION["verdieping"]; $telefoon = $_SESSION["telefoon"]; $netwerk = $_SESSION["netwerk"]; if ($oppervlakte <= 10) $tarief = 100; if ($oppervlakte > 10 && $oppervlakte <= 20) $tarief = 90; if ($oppervlakte > 20) $tarief = 80; if($verdieping == 1) { $prijsVerdieping = $oppervlakte * 120; } else { $prijsVerdieping = 0; } if(($telefoon == 1) && ($netwerk == 1)) { $prijsCom = 30; // never get this value, it always uses 20 } if(($telefoon == 1) || ($netwerk == 1)) { $prijsCom = 20; } $prijsOpp = $tarief * $oppervlakte; // works $totalePrijs = $prijsOpp + $prijsVerdieping + $prijsCom; //prijsCom value is always wrong Regards.

  Read the article

• Weird seg fault problem

  - by bluedaemon

  Greetings, I'm having a weird seg fault problem. My application dumps a core file at runtime. After digging into it I found it died in this block: #include <lib1/c.h> ... x::c obj; obj.func1(); I defined class c in a library lib1: namespace x { struct c { c(); ~c(); void fun1(); vector<char *> _data; }; } x::c::c() { } x::c::~c() { for ( int i = 0; i < _data.size(); ++i ) delete _data[i]; } I could not figure it out for some time till I ran nm on the lib1.so file: there are more function definitions than I defined: x::c::c() x::c::c() x::c::~c() x::c::~c() x::c::func1() x::c::func2() After searching in code base I found someone else defined a class with same name in same namespace, but in another library lib2 as follows: namespace x { struct c { c(); ~c(); void func2(); vector<string> strs_; }; } x::c::c() { } x::c::~c() { } My application links to lib2, which has dependency on lib1. This interesting behavior brings several questions: Why would it even work? I would expect a "multiple definitions" error while linking against lib2 (which depends upon lib1) but never had such. The application seems to be doing what's defined in func1 except it dumps a core at runtime. After attaching debugger, I found my application calls the ctor of class c in lib2, then calls func1 (defined in lib1). When going out of scope it calls dtor of class c in lib2, where the seg fault occurs. Can anybody teach me how this could even occur? How can I prevent such problems from happening again? Is there any C++ syntax I can use? Forgot to mention I'm using g++ 4.1 on RHEL4, thank you very much!

  Read the article

• Week in Geek: USDA Chooses Microsoft for Cloud Services Edition

  - by Asian Angel

  This week we learned how to create geeky LED holiday lights with old bottles, dig deeper in Windows Defrag via the command prompt, use Google Chrome’s drag/drop feature to upload files easier, find great gift recommendations by looking through the How-To Geek holiday gift guide, and have fun adding Merry Christmas fonts to our computers. Photo by ntr23. Random Geek Links It has been a busy week, so we have extra news link goodness with information that is good for you to know. USDA making the move to Microsoft The U.S. Department of Agriculture has announced that it has chosen Microsoft to host things like e-mail, instant messaging, and collaboration through the software giant’s Business Productivity Online Suite. Google says it was cut off from USDA project bid Google is claiming that it was not given a chance to bid on a cloud-computing project for the U.S. Department of Agriculture, for which the contract was awarded to rival Microsoft. Apache is being forced into a Java Fork When Oracle rolled over Apache and Google’s objections to its Java plans in December, the scene was set for Apache to leave and, eventually, force a Java code fork. Tumblr explains daylong outage After experiencing an outage that started on Sunday afternoon and stretched through most of the day yesterday, Tumblr has explained what happened. Google demos Chrome OS, launches pilot program During a press briefing this week in San Francisco, Google launched the Chrome application store and demonstrated Chrome OS, its browser-centric netbook operating system. Don’t expect Spotify in U.S. this holiday season As of last week, Spotify had yet to sign a single licensing deal with a major label, after spending more than a year negotiating, multiple music sources told CNET. December 2010 Patch Tuesday will come with most bulletins ever According to the Microsoft Security Response Center, Microsoft will issue 17 Security Bulletins addressing 40 vulnerabilities on Tuesday, December 14. It will also host a webcast to address customer questions the following day. Hacker plants back door in Symbian firmware Indian hacker Atul Alex has had a look at the firmware for Symbian S60 smartphones and come up with a back door for it. PC quarantines raise tough complexities The concept of quarantining PCs to prevent widespread infection is “interesting, but difficult to implement, with far too many problems”, said security experts. Symantec: DDoS attacks hard to defend It has surfaced that the distributed denial of service (DDoS) attacks on Visa and MasterCard Web sites on Wednesday were carried out by a toolkit known as low orbit ion cannon (LOIC). Web Sockets and the risks of unfinished standards Enthusiasm for a promising new standard called Web Sockets has quickly cooled in some quarters as a potential security problem led some browser makers to hastily postpone support. Internet Explorer 9 to get tracking protection Microsoft is making changes to Internet Explorer 9’s security features that will better enable users to keep sites from tracking their activity across browsing sessions. NASA sold PCs with sensitive data NASA failed to remove sensitive data from computers that it sold, according to an audit report released this week. Cybercrooks create fake Amazon receipts The bad guys have created yet another online scam, this one involving fake Amazon receipts. World of Warcraft character move fees waived Until December 22, Blizzard will allow free realm transfers from 25 highly populated servers to alleviate log-in queues or performance issues. (The free transfers are one-way and one-time only.) SpaceX Dragon reaches orbit atop a Falcon with a fiery tail The Space Exploration Technologies corporation has become the first nongovernmental entity to put a vehicle into low Earth orbit. Geek Video of the Week If birds have wings, then why are the Angry Birds using slingshots? Photo by Dorkly Bits. Wait… Birds have Wings, Why are the Angry Ones Using Slingshots? Sysadmin Geek Tips How To Setup Email Alerts on Linux Using Gmail or SMTP Linux machines may require administrative intervention in countless ways, but without manually logging into them how would you know about it? Here’s how to setup emails to get notified when your machines want some tender love and attention. Random TinyHacker Links Red Panda Webcam Support Firefox and the Knoxville Zoo’s Red Panda program. Christmas Icons (Icons we like) Superb set of holiday icons by lgp85 at deviantArt. Download the .zip and use as .png or convert to .ico at Convertico.com or with tiny app Imagicon. Super User Questions Enjoy reading the great answers to this week’s popular questions from Super User Useful USB boot disks? DVD/CD burning .zip: is it more reliable, faster, longer lasting to burn a zip of files rather than the files as a folder? What are other ways to backup my files if I do not have an external drive? Anti virus what is the difference between these all? How can I block all Facebook elements/content? How-To Geek Weekly Article Recap Have you had a busy week between work and preparing for the holidays? Get caught up on your HTG reading with our hottest articles of the week. 20 Windows Keyboard Shortcuts You Might Not Know The 50 Best Registry Hacks that Make Windows Better LCD? LED? Plasma? The How-To Geek Guide to HDTV Technology HTG Explains: Which Linux File System Should You Choose? How to Use and Customize Google Chrome Web Apps One Year Ago on How-To Geek This week’s batch of retro geeky goodness is all about customizing Windows 7. ClassicShell Adds Classic Start Menu and Explorer Features to Windows 7 Get an Aero-Styled Classic Start Menu in Windows 7 Customize the Windows 7 Logon Screen Get the Classic Style Network Activity Indicator Back in Windows 7 How To Enable Check Boxes for Items In Windows 7 The Geek Note We would like you to join us in welcoming Jason Fitzpatrick to the writing staff here at How-To Geek. He started with us this past week, so take some time to read through his articles about the Wii, Kindle, & PlayStation 2 Peripherals and leave a friendly comment to say “Hi”! Got a great tip to share? Make sure to send it in to us at [email protected]. Photo by real00. Latest Features How-To Geek ETC The 50 Best Registry Hacks that Make Windows Better The How-To Geek Holiday Gift Guide (Geeky Stuff We Like) LCD? LED? Plasma? The How-To Geek Guide to HDTV Technology The How-To Geek Guide to Learning Photoshop, Part 8: Filters Improve Digital Photography by Calibrating Your Monitor Our Favorite Tech: What We’re Thankful For at How-To Geek Settle into Orbit with the Voyage Theme for Chrome and Iron Awesome Safari Compass Icons Set Escape from the Exploding Planet Wallpaper Move Your Tumblr Blog to WordPress Pytask is an Easy to Use To-Do List Manager for Your Ubuntu System Snowy Christmas House Personas Theme for Firefox

  Read the article

• GZip/Deflate Compression in ASP.NET MVC

  - by Rick Strahl

  A long while back I wrote about GZip compression in ASP.NET. In that article I describe two generic helper methods that I've used in all sorts of ASP.NET application from WebForms apps to HttpModules and HttpHandlers that require gzip or deflate compression. The same static methods also work in ASP.NET MVC. Here are the two routines:/// <summary> /// Determines if GZip is supported /// </summary> /// <returns></returns> public static bool IsGZipSupported() { string AcceptEncoding = HttpContext.Current.Request.Headers["Accept-Encoding"]; if (!string.IsNullOrEmpty(AcceptEncoding) && (AcceptEncoding.Contains("gzip") || AcceptEncoding.Contains("deflate"))) return true; return false; } /// <summary> /// Sets up the current page or handler to use GZip through a Response.Filter /// IMPORTANT: /// You have to call this method before any output is generated! /// </summary> public static void GZipEncodePage() { HttpResponse Response = HttpContext.Current.Response; if (IsGZipSupported()) { string AcceptEncoding = HttpContext.Current.Request.Headers["Accept-Encoding"]; if (AcceptEncoding.Contains("gzip")) { Response.Filter = new System.IO.Compression.GZipStream(Response.Filter, System.IO.Compression.CompressionMode.Compress); Response.Headers.Remove("Content-Encoding"); Response.AppendHeader("Content-Encoding", "gzip"); } else { Response.Filter = new System.IO.Compression.DeflateStream(Response.Filter, System.IO.Compression.CompressionMode.Compress); Response.Headers.Remove("Content-Encoding"); Response.AppendHeader("Content-Encoding", "deflate"); } } // Allow proxy servers to cache encoded and unencoded versions separately Response.AppendHeader("Vary", "Content-Encoding"); } The first method checks whether the client sending the request includes the accept-encoding for either gzip or deflate, and if if it does it returns true. The second function uses IsGzipSupported() to decide whether it should encode content and uses an Response Filter to do its job. Basically response filters look at the Response output stream as it's written and convert the data flowing through it. Filters are a bit tricky to work with but the two .NET filter streams for GZip and Deflate Compression make this a snap to implement. In my old code and even now in MVC I can always do:public ActionResult List(string keyword=null, int category=0) { WebUtils.GZipEncodePage(); …} to encode my content. And that works just fine. The proper way: Create an ActionFilterAttribute However in MVC this sort of thing is typically better handled by an ActionFilter which can be applied with an attribute. So to be all prim and proper I created an CompressContentAttribute ActionFilter that incorporates those two helper methods and which looks like this:/// <summary> /// Attribute that can be added to controller methods to force content /// to be GZip encoded if the client supports it /// </summary> public class CompressContentAttribute : ActionFilterAttribute { /// <summary> /// Override to compress the content that is generated by /// an action method. /// </summary> /// <param name="filterContext"></param> public override void OnActionExecuting(ActionExecutingContext filterContext) { GZipEncodePage(); } /// <summary> /// Determines if GZip is supported /// </summary> /// <returns></returns> public static bool IsGZipSupported() { string AcceptEncoding = HttpContext.Current.Request.Headers["Accept-Encoding"]; if (!string.IsNullOrEmpty(AcceptEncoding) && (AcceptEncoding.Contains("gzip") || AcceptEncoding.Contains("deflate"))) return true; return false; } /// <summary> /// Sets up the current page or handler to use GZip through a Response.Filter /// IMPORTANT: /// You have to call this method before any output is generated! /// </summary> public static void GZipEncodePage() { HttpResponse Response = HttpContext.Current.Response; if (IsGZipSupported()) { string AcceptEncoding = HttpContext.Current.Request.Headers["Accept-Encoding"]; if (AcceptEncoding.Contains("gzip")) { Response.Filter = new System.IO.Compression.GZipStream(Response.Filter, System.IO.Compression.CompressionMode.Compress); Response.Headers.Remove("Content-Encoding"); Response.AppendHeader("Content-Encoding", "gzip"); } else { Response.Filter = new System.IO.Compression.DeflateStream(Response.Filter, System.IO.Compression.CompressionMode.Compress); Response.Headers.Remove("Content-Encoding"); Response.AppendHeader("Content-Encoding", "deflate"); } } // Allow proxy servers to cache encoded and unencoded versions separately Response.AppendHeader("Vary", "Content-Encoding"); } } It's basically the same code wrapped into an ActionFilter attribute, which intercepts requests MVC requests to Controller methods and lets you hook up logic before and after the methods have executed. Here I want to override OnActionExecuting() which fires before the Controller action is fired. With the CompressContentAttribute created, it can now be applied to either the controller as a whole:[CompressContent] public class ClassifiedsController : ClassifiedsBaseController { … } or to one of the Action methods:[CompressContent] public ActionResult List(string keyword=null, int category=0) { … } The former applies compression to every action method, while the latter is selective and only applies it to the individual action method. Is the attribute better than the static utility function? Not really, but it is the standard MVC way to hook up 'filter' content and that's where others are likely to expect to set options like this. In fact,  you have a bit more control with the utility function because you can conditionally apply it in code, but this is actually much less likely in MVC applications than old WebForms apps since controller methods tend to be more focused. Compression Caveats Http compression is very cool and pretty easy to implement in ASP.NET but you have to be careful with it - especially if your content might get transformed or redirected inside of ASP.NET. A good example, is if an error occurs and a compression filter is applied. ASP.NET errors don't clear the filter, but clear the Response headers which results in some nasty garbage because the compressed content now no longer matches the headers. Another issue is Caching, which has to account for all possible ways of compression and non-compression that the content is served. Basically compressed content and caching don't mix well. I wrote about several of these issues in an old blog post and I recommend you take a quick peek before diving into making every bit of output Gzip encoded. None of these are show stoppers, but you have to be aware of the issues. Related Posts GZip Compression with ASP.NET Content ASP.NET GZip Encoding Caveats© Rick Strahl, West Wind Technologies, 2005-2012Posted in ASP.NET  MVC   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (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); })();

  Read the article

• Reporting Services - It's a Wrap!

  - by smisner

  If you have any experience at all with Reporting Services, you have probably developed a report using the matrix data region. It's handy when you want to generate columns dynamically based on data. If users view a matrix report online, they can scroll horizontally to view all columns and all is well. But if they want to print the report, the experience is completely different and you'll have to decide how you want to handle dynamic columns. By default, when a user prints a matrix report for which the number of columns exceeds the width of the page, Reporting Services determines how many columns can fit on the page and renders one or more separate pages for the additional columns. In this post, I'll explain two techniques for managing dynamic columns. First, I'll show how to use the RepeatRowHeaders property to make it easier to read a report when columns span multiple pages, and then I'll show you how to "wrap" columns so that you can avoid the horizontal page break. Included with this post are the sample RDLs for download. First, let's look at the default behavior of a matrix. A matrix that has too many columns for one printed page (or output to page-based renderer like PDF or Word) will be rendered such that the first page with the row group headers and the inital set of columns, as shown in Figure 1. The second page continues by rendering the next set of columns that can fit on the page, as shown in Figure 2.This pattern continues until all columns are rendered. The problem with the default behavior is that you've lost the context of employee and sales order - the row headers - on the second page. That makes it hard for users to read this report because the layout requires them to flip back and forth between the current page and the first page of the report. You can fix this behavior by finding the RepeatRowHeaders of the tablix report item and changing its value to True. The second (and subsequent pages) of the matrix now look like the image shown in Figure 3. The problem with this approach is that the number of printed pages to flip through is unpredictable when you have a large number of potential columns. What if you want to include all columns on the same page? You can take advantage of the repeating behavior of a tablix and get repeating columns by embedding one tablix inside of another. For this example, I'm using SQL Server 2008 R2 Reporting Services. You can get similar results with SQL Server 2008. (In fact, you could probably do something similar in SQL Server 2005, but I haven't tested it. The steps would be slightly different because you would be working with the old-style matrix as compared to the new-style tablix discussed in this post.) I created a dataset that queries AdventureWorksDW2008 tables: SELECT TOP (100) e.LastName + ', ' + e.FirstName AS EmployeeName, d.FullDateAlternateKey, f.SalesOrderNumber, p.EnglishProductName, sum(SalesAmount) as SalesAmount FROM FactResellerSales AS f INNER JOIN DimProduct AS p ON p.ProductKey = f.ProductKey INNER JOIN DimDate AS d ON d.DateKey = f.OrderDateKey INNER JOIN DimEmployee AS e ON e.EmployeeKey = f.EmployeeKey GROUP BY p.EnglishProductName, d.FullDateAlternateKey, e.LastName + ', ' + e.FirstName, f.SalesOrderNumber ORDER BY EmployeeName, f.SalesOrderNumber, p.EnglishProductName To start the report: Add a matrix to the report body and drag Employee Name to the row header, which also creates a group. Next drag SalesOrderNumber below Employee Name in the Row Groups panel, which creates a second group and a second column in the row header section of the matrix, as shown in Figure 4. Now for some trickiness. Add another column to the row headers. This new column will be associated with the existing EmployeeName group rather than causing BIDS to create a new group. To do this, right-click on the EmployeeName textbox in the bottom row, point to Insert Column, and then click Inside Group-Right. Then add the SalesOrderNumber field to this new column. By doing this, you're creating a report that repeats a set of columns for each EmployeeName/SalesOrderNumber combination that appears in the data. Next, modify the first row group's expression to group on both EmployeeName and SalesOrderNumber. In the Row Groups section, right-click EmployeeName, click Group Properties, click the Add button, and select [SalesOrderNumber]. Now you need to configure the columns to repeat. Rather than use the Columns group of the matrix like you might expect, you're going to use the textbox that belongs to the second group of the tablix as a location for embedding other report items. First, clear out the text that's currently in the third column - SalesOrderNumber - because it's already added as a separate textbox in this report design. Then drag and drop a matrix into that textbox, as shown in Figure 5. Again, you need to do some tricks here to get the appearance and behavior right. We don't really want repeating rows in the embedded matrix, so follow these steps: Click on the Rows label which then displays RowGroup in the Row Groups pane below the report body. Right-click on RowGroup,click Delete Group, and select the option to delete associated rows and columns. As a result, you get a modified matrix which has only a ColumnGroup in it, with a row above a double-dashed line for the column group and a row below the line for the aggregated data. Let's continue: Drag EnglishProductName to the data textbox (below the line). Add a second data row by right-clicking EnglishProductName, pointing to Insert Row, and clicking Below. Add the SalesAmount field to the new data textbox. Now eliminate the column group row without eliminating the group. To do this, right-click the row above the double-dashed line, click Delete Rows, and then select Delete Rows Only in the message box. Now you're ready for the fit and finish phase: Resize the column containing the embedded matrix so that it fits completely. Also, the final column in the matrix is for the column group. You can't delete this column, but you can make it as small as possible. Just click on the matrix to display the row and column handles, and then drag the right edge of the rightmost column to the left to make the column virtually disappear. Next, configure the groups so that the columns of the embedded matrix will wrap. In the Column Groups pane, right-click ColumnGroup1 and click on the expression button (labeled fx) to the right of Group On [EnglishProductName]. Replace the expression with the following: =RowNumber("SalesOrderNumber" ). We use SalesOrderNumber here because that is the name of the group that "contains" the embedded matrix. The next step is to configure the number of columns to display before wrapping. Click any cell in the matrix that is not inside the embedded matrix, and then double-click the second group in the Row Groups pane - SalesOrderNumber. Change the group expression to the following expression: =Ceiling(RowNumber("EmployeeName")/3) The last step is to apply formatting. In my example, I set the SalesAmount textbox's Format property to C2 and also right-aligned the text in both the EnglishProductName and the SalesAmount textboxes. And voila - Figure 6 shows a matrix report with wrapping columns. Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

  Read the article

• Twitter traffic might not be what it seems

  - by Piet

  Are you using bit.ly stats to measure interest in the links you post on twitter? I’ve been hearing for a while about people claiming to get the majority of their traffic originating from twitter these days. Now, I’ve been playing with the twitter ruby gem recently, doing various experiments which I’ll not go into detail here because they could be regarded as spamming… if I’d conduct them on a large scale, that is. It’s scary to see people actually engaging with @replies crafted with some regular expressions and eliza-like trickery on status updates found using the twitter api. I’m wondering how Twitter is going to contain the coming spam-flood. When posting links I used bit.ly as url shortener, since this one seems to be the de-facto standard on twitter. A nice thing about bit.ly is that it shows some basic stats about the redirects it performs for your shortened links. To my surprise, most links posted almost immediately resulted in several visitors. Now, seeing that I was posting the links together with some information concerning what the link is about, I concluded that the people who were actually clicking the links should be very targeted visitors. This felt a bit like free adwords, and I suddenly started to understand why everyone was raving about getting traffic from twitter. How wrong I was! (and I think several 1000 online marketers with me) On the destination site I used a traffic logging solution that works by including a little javascript snippet in your pages. It seemed that somehow all visitors disappeared after the bit.ly redirect and before getting to the site, because I was hardly seeing any visitors there. So I started investigating what was happening: by looking at the logfiles of the destination site, and by making my own ’shortened’ urls by doing redirects using a very short domain name I own. This way, I could check the apache access_log before the redirects. Most user agents turned out to be bots without a doubt. Here’s an excerpt of user-agents awk’ed from apache’s access_log for a time period of about one hour, right after posting some links: AideRSS 2.0 (postrank.com) Java/1.6.0_13 Java/1.6.0_14 libwww-perl/5.816 MLBot (www.metadatalabs.com/mlbot) Mozilla/4.0 (compatible;MSIE 5.01; Windows -NT 5.0 - real-url.org) Mozilla/5.0 (compatible; Twitturls; +http://twitturls.com) Mozilla/5.0 (compatible; Viralheat Bot/1.0; +http://www.viralheat.com/) Mozilla/5.0 (Danger hiptop 4.6; U; rv:1.7.12) Gecko/20050920 Mozilla/5.0 (X11; U; Linux i686; en-us; rv:1.9.0.2) Gecko/2008092313 Ubuntu/9.04 (jaunty) Firefox/3.5 OpenCalaisSemanticProxy PycURL/7.18.2 PycURL/7.19.3 Python-urllib/1.17 Twingly Recon twitmatic Twitturly / v0.6 Wget/1.10.2 (Red Hat modified) Wget/1.11.1 (Red Hat modified) Of the few user-agents that seem ‘real’ at first, half are originating from an ip-address used by Amazon EC2. And I doubt people are setting op proxies on there. Oh yeah, Googlebot (the real deal, from a legit google owned address) is sucking up posted links like fresh oysters. I guess google is trying to make sure in advance to never be beaten by twitter in the ‘realtime search’ department. Actually, I think it’d be almost stupid NOT to post any new pages/posts/websites on Twitter, it must be one of the fastest ways to get a Googlebot visit. Same experiment with a real, established twitter account Now, because I was posting the url’s either as ’status’ messages or directed @people, on a test-account with hardly any (human) followers, I checked again using the twitter accounts from a commercial site I’m involved with. These accounts all have between 500 and 1000 targeted (I think) followers. I checked the destination access_logs and also added ‘my’ redirect after the bit.ly redirect: same results, although seemingly a bit higher real visitor/bot ratio. Btw: one of these account was ‘punished’ with a 1 week lock recently because the same (1 one!) status update was sent that was sent right before using another account. They got an email explaining the lock because the account didn’t act according to their TOS. I can’t find anything in their TOS about it, can you? I don’t think Twitter is on the right track punishing a legit account, knowing the trickery I had been doing with it’s api went totally unpunished. I might be wrong though, I often am. On the other hand: this commercial site reported targeted traffic and actual signups from visitors coming from Twitter. The ones that are really real visitors are also very targeted. I’m just not sure if the amount of work involved could hold up against an adwords campaign. Reposting the same link over and over again helps On thing I noticed: It helps to keep on reposting the same links with regular intervals. I guess most people only look at their first page when checking out recent posts of the ones they’re following, or don’t look too far back when performing a search. Now, this probably isn’t according to the twitter TOS. Actually, it might be spamming but no-one is obligated to follow anyone else of course. This way, I was getting more real visitors and less bots. To my surprise (when my programmer’s hat is on) there were still repeated visits from the same bots coming from the same ip-addresses. Did they expect to find something else when visiting for a 2nd or 3rd time? (actually,this gave me an idea: you can’t change a link once it’s posted, but you can change where it redirects to) Most bots were smart enough not to follow the same link again though. Are you successful in getting real visitors from Twitter? Are you only relying on bit.ly to provide traffic stats?

  Read the article

• Michael Crump&rsquo;s notes for 70-563 PRO &ndash; Designing and Developing Windows Applications usi

  - by mbcrump

  TIME TO GO PRO! This is my notes for 70-563 PRO – Designing and Developing Windows Applications using .NET Framework 3.5 I created it using several resources (various certification web sites, msdn, official ms 70-548 book). The reason that I created this review is because a) I am taking the exam. b) MS did not create a book for this exam. Use the(MS 70-548)book. c) To make sure I am familiar with each before the exam. I hope that it provides a good start for your own notes. I hope that someone finds this useful. At least, it will give you a starting point of what to expect to know on the PRO exam. Also, for those wondering, the PRO exam does contains very little code. It is basically all theory. 1. Validation Controls – How to prevent users from entering invalid data on forms. (MaskedTextBox control and RegEx) 2. ServiceController – used to start and control the behavior of existing services. 3. User Feedback (know winforms Status Bar, Tool Tips, Color, Error Provider, Context-Sensitive and Accessibility) 4. Specific (derived) exceptions must be handled before general (base class) exceptions. By moving the exception handling for the base type Exception to after exception handling of ArgumentNullException, all ArgumentNullException thrown by the Helper method will be caught and logged correctly. 5. A heartbeat method is a method exposed by a Web service that allows external applications to check on the status of the service. 6. New users must master key tasks quickly. Giving these tasks context and appropriate detail will help. However, advanced users will demand quicker paths. Shortcuts, accelerators, or toolbar buttons will speed things along for the advanced user. 7. MSBuild uses project files to instruct the build engine what to build and how to build it. MSBuild project files are XML files that adhere to the MSBuild XML schema. The MSBuild project files contain complete file, build action, and dependency information for each individual projects. 8. Evaluating whether or not to fix a bug involves a triage process. You must identify the bug's impact, set the priority, categorize it, and assign a developer. Many times the person doing the triage work will assign the bug to a developer for further investigation. In fact, the workflow for the bug work item inside of Team System supports this step. Developers are often asked to assess the impact of a given bug. This assessment helps the person doing the triage make a decision on how to proceed. When assessing the impact of a bug, you should consider time and resources to fix it, bug risk, and impacts of the bug. 9. In large projects it is generally impossible and unfeasible to fix all bugs because of the impact on schedule and budget. 10. Code reviews should be conducted by a technical lead or a technical peer. 11. Testing Applications 12. WCF Services – application state 13. SQL Server 2005 / 2008 Express Edition – reliable storage of data / Microsoft SQL Server 3.5 Compact Database– used for client computers to retrieve and save data from a shared location. 14. SQL Server 2008 Compact Edition – used for minimum possible memory and can synchronize data with a corporate SQL Server 2008 Database. Supports offline user and minimum dependency on external components. 15. MDI and SDI Forms (specifically IsMDIContainer) 16. GUID – in the case of data warehousing, it is important to define unique keys. 17. Encrypting / Security Data 18. Understanding of Isolated Storage/Proper location to store items 19. LINQ to SQL 20. Multithreaded access 21. ADO.NET Entity Framework model 22. Marshal.ReleaseComObject 23. Common User Interface Layout (ComboBox, ListBox, Listview, MaskedTextBox, TextBox, RichTextBox, SplitContainer, TableLayoutPanel, TabControl) 24. DataSets Class - http://msdn.microsoft.com/en-us/library/system.data.dataset%28VS.71%29.aspx 25. SQL Server 2008 Reporting Services (SSRS) 26. SystemIcons.Shield (Vista UAC) 27. Leverging stored procedures to perform data manipulation for a database schema that can change. 28. DataContext 29. Microsoft Windows Installer Packages, ClickOnce(bootstrapping features), XCopy. 30. Client Application Services – will authenticate users by using the same data source as a ASP.NET web application. 31. SQL Server 2008 Caching 32. StringBuilder 33. Accessibility Guidelines for Windows Applications http://msdn.microsoft.com/en-us/library/ms228004.aspx 34. Logging erros 35. Testing performance related issues. 36. Role Based Security, GenericIdentity and GenericPrincipal 37. System.Net.CookieContainer will store session data for webapps (see isolated storage for winforms) 38. .NET CLR Profiler tool will identify objects that cause performance issues. 39. ADO.NET Synchronization (SyncGroup) 40. Globalization - CultureInfo 41. IDisposable Interface- reports on several questions relating to this. 42. Adding timestamps to determine whether data has changed or not. 43. Converting applications to .NET Framework 3.5 44. MicrosoftReportViewer 45. Composite Controls 46. Windows Vista KNOWN folders. 47. Microsoft Sync Framework 48. TypeConverter -Provides a unified way of converting types of values to other types, as well as for accessing standard values and sub properties. http://msdn.microsoft.com/en-us/library/system.componentmodel.typeconverter.aspx 49. Concurrency control mechanisms The main categories of concurrency control mechanisms are: Optimistic - Delay the checking of whether a transaction meets the isolation rules (e.g., serializability and recoverability) until its end, without blocking any of its (read, write) operations, and then abort a transaction, if the desired rules are violated. Pessimistic - Block operations of a transaction, if they may cause violation of the rules. Semi-optimistic - Block operations in some situations, and do not block in other situations, while delaying rules checking to transaction's end, as done with optimistic. 50. AutoResetEvent 51. Microsoft Messaging Queue (MSMQ) 4.0 52. Bulk imports 53. KeyDown event of controls 54. WPF UI components 55. UI process layer 56. GAC (installing, removing and queuing) 57. Use a local database cache to reduce the network bandwidth used by applications. 58. Sound can easily be annoying and distracting to users, so use it judiciously. Always give users the option to turn sound off. Because a user might have sound off, never convey important information through sound alone.

  Read the article

• T4 Template error - Assembly Directive cannot locate referenced assembly in Visual Studio 2010 proje

  - by CodeSniper

  I ran into the following error recently in Visual Studio 2010 while trying to port Phil Haack’s excellent T4CSS template which was originally built for Visual Studio 2008.   The Problem Error Compiling transformation: Metadata file 'dotless.Core' could not be found In “T4 speak”, this simply means that you have an Assembly directive in your T4 template but the T4 engine was not able to locate or load the referenced assembly. In the case of the T4CSS Template, this was a showstopper for making it work in Visual Studio 2010. On a side note: The T4CSS template is a sweet little wrapper to allow you to use DotLessCss to generate static .css files from .less files rather than using their default HttpHandler or command-line tool.    If you haven't tried DotLessCSS yet, go check it out now!  In short, it is a tool that allows you to templatize and program your CSS files so that you can use variables, expressions, and mixins within your CSS which enables rapid changes and a lot of developer-flexibility as you evolve your CSS and UI. Back to our regularly scheduled program… Anyhow, this post isn't about DotLessCss, its about the T4 Templates and the errors I ran into when converting them from Visual Studio 2008 to Visual Studio 2010. In VS2010, there were quite a few changes to the T4 Template Engine; most were excellent changes, but this one bit me with T4CSS: “Project assemblies are no longer used to resolve template assembly directives.” In VS2008, if you wanted to reference a custom assembly in your T4 Template (.tt file) you would simply right click on your project, choose Add Reference and select that assembly.  Afterwards you were allowed to use the following syntax in your T4 template to tell it to look at the local references: <#@ assembly name="dotless.Core.dll" #> This told the engine to look in the “usual place” for the assembly, which is your project references. However, this is exactly what they changed in VS2010.  They now basically sandbox the T4 Engine to keep your T4 assemblies separate from your project assemblies.  This can come in handy if you want to support different versions of an assembly referenced both by your T4 templates and your project. Who broke the build?  Oh, Microsoft Did! In our case, this change causes a problem since the templates are no longer compatible when upgrading to VS 2010 – thus its a breaking change.  So, how do we make this work in VS 2010? Luckily, Microsoft now offers several options for referencing assemblies from T4 Templates: GAC your assemblies and use Namespace Reference or Fully Qualified Type Name Use a hard-coded Fully Qualified UNC path Copy assembly to Visual Studio "Public Assemblies Folder" and use Namespace Reference or Fully Qualified Type Name.  Use or Define a Windows Environment Variable to build a Fully Qualified UNC path. Use a Visual Studio Macro to build a Fully Qualified UNC path. Option #1 & 2 were already supported in Visual Studio 2008, so if you want to keep your templates compatible with both Visual Studio versions, then you would have to adopt one of these approaches. Yakkety Yak, use the GAC! Option #1 requires an additional pre-build step to GAC the referenced assembly, which could be a pain.  But, if you go that route, then after you GAC, all you need is a simple type name or namespace reference such as: <#@ assembly name="dotless.Core" #> Hard Coding aint that hard! The other option of using hard-coded paths in Option #2 is pretty impractical in most situations since each developer would have to use the same local project folder paths, or modify this setting each time for their local machines as well as for production deployment.  However, if you want to go that route, simply use the following assembly directive style: <#@ assembly name="C:\Code\Lib\dotless.Core.dll" #> Lets go Public! Option #3, the Visual Studio Public Assemblies Folder, is the recommended place to put commonly used tools and libraries that are only needed for Visual Studio.  Think of it like a VS-only GAC.  This is likely the best place for something like dotLessCSS and is my preferred solution.  However, you will need to either use an installer or a pre-build action to copy the assembly to the right folder location.   Normally this is located at:  C:\Program Files (x86)\Microsoft Visual Studio 10.0\Common7\IDE\PublicAssemblies Once you have copied your assembly there, you use the type name or namespace syntax again: <#@ assembly name="dotless.Core" #> Save the Environment! Option #4, using a Windows Environment Variable, is interesting for enterprise use where you may have standard locations for files, but less useful for demo-code, frameworks, and products where you don't have control over the local system.  The syntax for including a environment variable in your assembly directive looks like the following, just as you would expect: <#@ assembly name="%mypath%\dotless.Core.dll" #> “mypath” is a Windows environment variable you setup that points to some fully qualified UNC path on your system.  In the right situation this can be a great solution such as one where you use a msi installer for deployment, or where you have a pre-existing environment variable you can re-use. OMG Macros! Finally, Option #5 is a very nice option if you want to keep your T4 template’s assembly reference local and relative to the project or solution without muddying-up your dev environment or GAC with extra deployments.  An example looks like this: <#@ assembly name="$(SolutionDir)lib\dotless.Core.dll" #> In this example, I’m using the “SolutionDir” VS macro so I can reference an assembly in a “/lib” folder at the root of the solution.   This is just one of the many macros you can use.  If you are familiar with creating Pre/Post-build Event scripts, you can use its dialog to look at all of the different VS macros available. This option gives the best solution for local assemblies without the hassle of extra installers or other setup before the build.   However, its still not compatible with Visual Studio 2008, so if you have a T4 Template you want to use with both, then you may have to create multiple .tt files, one for each IDE version, or require the developer to set a value in the .tt file manually.   I’m not sure if T4 Templates support any form of compiler switches like “#if (VS2010)”  statements, but it would definitely be nice in this case to switch between this option and one of the ones more compatible with VS 2008. Conclusion As you can see, we went from 3 options with Visual Studio 2008, to 5 options (plus one problem) with Visual Studio 2010.  As a whole, I think the changes are great, but the short-term growing pains during the migration may be annoying until we get used to our new found power. Hopefully this all made sense and was helpful to you.  If nothing else, I’ll just use it as a reference the next time I need to port a T4 template to Visual Studio 2010.  Happy T4 templating, and “May the fourth be with you!”

  Read the article

• Who IS Brian Solis?

  - by Michael Snow

  Q: Brian, Welcome to the WebCenter Blog. Can you tell our readers your current role and what career path brought you here? A: I’m proudly serving as a principal analyst at Altimeter Group, a research based advisory firm in Silicon Valley. My career path, well, let’s just say it’s a long and winding road. As a kid, I was fascinated with technology. I learned programming at an early age and found myself naturally drawn to all things tech. I started my career as a database programmer at a technology marketing agency in Southern California. When I saw the chance to work with tech companies and help them better market their capabilities to businesses and consumers, I switched focus from programming to marketing and advertising. As technologist, my approach to marketing was different. I didn’t believe in hype, fluff or buzz words. I believed in translating features into benefits and specifications and capabilities into solutions for real world problems and opportunities. In the mid 90’s I experimented with direct to consumer/customer engagement in dedicated technology forums and boards. I quickly realized that the entire approach to do so would need to change. Therefore, I learned and developed new methods for a more social and informed way of engaging people in ways that helped them, marketed the company, and also tied to tangible benefits for the company. This work would lead me to start an agency in 1999 dedicated to interactive marketing. As I continued to experiment with interactive platforms, I developed interesting methods for converting one-to-many forms of media into one-to-one-to-many programs. I ran that company until joining Altimeter Group. Along the way, in the early 2000s, I realized that everything was changing and that there were others like me finding success in what would become a more social form of media. I dedicated a significant amount of my time to sharing everything that I learned in the form of articles, blogs, and eventually books. My mission became to share my experience with anyone who’d listen. It would later become much bigger than marketing, this would lead to a decade of work, that still continues, in business transformation. Then and now, I find myself always assuming the role of a student. Q: As an industry analyst & technology change evangelist, what are you primarily focused on these days? A: As a digital analyst, I study how disruptive technology impacts business. As an aspiring social scientist, I study how technology affects human behavior. I explore both horizons professionally and personally to better understand the future of popular culture and also the opportunities that exist for organizations to improve relationships and experiences with customers and the people that are important to them. Q: People cite that the line between work and life is getting more and more blurred. Do you see your personal life influencing your professional work? A: The line between work and life isn’t blurred it’s been overtly crossed and erased. We live in an always on society. The digital lifestyle keeps us connected to one another it keeps us connected all the time. Whether your sending or checking email, trying to catch up, or simply trying to get ahead, people are spending the equivalent of an extra day at work in the time they spend out of work…working. That’s absurd. It’s a matter of survival. It’s also a matter of unintended, subconscious self-causation. We brought this on ourselves and continue to do so. Think about your day. You’re in meetings for the better part of each day. You probably spend evenings and weekends catching up on email and actually doing the work you couldn’t get to during the day. And, your co-workers and executives are doing the same thing. So if you try to slow down, you find yourself at a disadvantage as you’re willfully pulling yourself out of an unfortunate culture of whenever wherever business dynamics. If you’re unresponsive or unreachable, someone within your organization or on your team is accessible. Over time, this could contribute to unfavorable impressions. I choose to steer my life balance in ways that complement one another. But, I don’t pretend to have this figured out by any means. In fact, I find myself swimming upstream like those around me. It’s essentially a competition for relevance and at some point I’ll learn how to earn attention and relevance while redrawing the line between work and life. Q: How can people keep up with what you’re working on? A: The easy answer is that people can keep up with me at briansolis.com. But, I also try to reach people where their attention is focused. Whether it’s Facebook (facebook.com/briansolis), Twitter (@briansolis), Google+ (+briansolis), Youtube (briansolis.tv) or through books and conferences, people can usually find me in a place of their choosing. Q: Recently, you’ve been working with us here at Oracle on something exciting coming up later this week. What’s on the horizon? A: I spent some time with the Oracle team reviewing the idea of Digital Darwinism and how technology and society are evolving faster than many organizations can adapt. Digital Darwinism: How Brands Can Survive the Rapid Evolution of Society and Technology Thursday, December 13, 2012, 10 a.m. PT / 1 p.m. ET Q: You’ve been very actively pursued for media interviews and conference and company speaking engagements – anything you’d like to share to give us a sneak peak of what to expect on Thursday’s webcast? A: We’re inviting guests to join us online as we dive into the future of business and how the convergence of technology and connected consumerism would ultimately impact how business is done. It’ll be an exciting and revealing conversation that explores just how much everything is changing. We’ll also review the importance of adapting to emergent trends and how to compete for the future. It’s important to recognize that change is not happening to us, it’s happening because of us. We are part of the revolution and therefore we need to help organizations adapt from the inside out. Watch the Entire Oracle Social Business Thought Leaders Webcast Series On-Demand and Stay Tuned for More to Come in 2013!

  Read the article

• Cloud MBaaS : The Next Big Thing in Enterprise Mobility

  - by shiju

  In this blog post, I will take a look at Cloud Mobile Backend as a Service (MBaaS) and how we can leverage Cloud based Mobile Backend as a Service for building enterprise mobile apps. Today, mobile apps are incredibly significant in both consumer and enterprise space and the demand for the mobile apps is unbelievably increasing in day to day business. An enterprise can’t survive in business without a proper mobility strategy. A better mobility strategy and faster delivery of your mobile apps will give you an extra mileage for your business and IT strategy. So organizations and mobile developers are looking for different strategy for meeting this demand and adopting different development strategy for their mobile apps. Some developers are adopting hybrid mobile app development platforms, for delivering their products for multiple platforms, for fast time-to-market. Others are adopting a Mobile enterprise application platform (MEAP) such as Kony for their enterprise mobile apps for fast time-to-market and better business integration. The Challenges of Enterprise Mobility The real challenge of enterprise mobile apps, is not about creating the front-end environment or developing front-end for multiple platforms. The most important thing of enterprise mobile apps is to expose your enterprise data to mobile devices where the real pain is your business data might be residing in lot of different systems including legacy systems, ERP systems etc., and these systems will be deployed with lot of security restrictions. Exposing your data from the on-premises servers, is not a easy thing for most of the business organizations. Many organizations are spending too much time for their front-end development strategy, but they are really lacking for building a strategy on their back-end for exposing the business data to mobile apps. So building a REST services layer and mobile back-end services, on the top of legacy systems and existing middleware systems, is the key part of most of the enterprise mobile apps, where multiple mobile platforms can easily consume these REST services and other mobile back-end services for building mobile apps. For some mobile apps, we can’t predict its user base, especially for products where customers can gradually increase at any time. And for today’s mobile apps, faster time-to-market is very critical so that spending too much time for mobile app’s scalability, will not be worth. The real power of Cloud is the agility and on-demand scalability, where we can scale-up and scale-down our applications very easily. It would be great if we could use the power of Cloud to mobile apps. So using Cloud for mobile apps is a natural fit, where we can use Cloud as the storage for mobile apps and hosting mechanism for mobile back-end services, where we can enjoy the full power of Cloud with greater level of on-demand scalability and operational agility. So Cloud based Mobile Backend as a Service is great choice for building enterprise mobile apps, where enterprises can enjoy the massive scalability power of their mobile apps, provided by public cloud vendors such as Microsoft Windows Azure. Mobile Backend as a Service (MBaaS) We have discussed the key challenges of enterprise mobile apps and how we can leverage Cloud for hosting mobile backend services. MBaaS is a set of cloud-based, server-side mobile services for multiple mobile platforms and HTML5 platform, which can be used as a backend for your mobile apps with the scalability power of Cloud. The information below provides the key features of a typical MBaaS platform: Cloud based storage for your application data. Automatic REST API services on the application data, for CRUD operations. Native push notification services with massive scalability power. User management services for authenticate users. User authentication via Social accounts such as Facebook, Google, Microsoft, and Twitter. Scheduler services for periodically sending data to mobile devices. Native SDKs for multiple mobile platforms such as Windows Phone and Windows Store, Android, Apple iOS, and HTML5, for easily accessing the mobile services from mobile apps, with better security.  Typically, a MBaaS platform will provide native SDKs for multiple mobile platforms so that we can easily consume the server-side mobile services. MBaaS based REST APIs can use for integrating to enterprise backend systems. We can use the same mobile services for multiple platform so hat we can reuse the application logic to multiple mobile platforms. Public cloud vendors are building the mobile services on the top of their PaaS offerings. Windows Azure Mobile Services is a great platform for a MBaaS offering that is leveraging Windows Azure Cloud platform’s PaaS capabilities. Hybrid mobile development platform Titanium provides their own MBaaS services. LoopBack is a new MBaaS service provided by Node.js consulting firm StrongLoop, which can be hosted on multiple cloud platforms and also for on-premises servers. The Challenges of MBaaS Solutions If you are building your mobile apps with a new data storage, it will be very easy, since there is not any integration challenges you have to face. But most of the use cases, you have to extract your application data in which stored in on-premises servers which might be under VPNs and firewalls. So exposing these data to your MBaaS solution with a proper security would be a big challenge. The capability of your MBaaS vendor is very important as you have to interact with your legacy systems for many enterprise mobile apps. So you should be very careful about choosing for MBaaS vendor. At the same time, you should have a proper strategy for mobilizing your application data which stored in on-premises legacy systems, where your solution architecture and strategy is more important than platforms and tools.  Windows Azure Mobile Services Windows Azure Mobile Services is an MBaaS offerings from Windows Azure cloud platform. IMHO, Microsoft Windows Azure is the best PaaS platform in the Cloud space. Windows Azure Mobile Services extends the PaaS capabilities of Windows Azure, to mobile devices, which can be used as a cloud backend for your mobile apps, which will provide global availability and reach for your mobile apps. Windows Azure Mobile Services provides storage services, user management with social network integration, push notification services and scheduler services and provides native SDKs for all major mobile platforms and HTML5. In Windows Azure Mobile Services, you can write server-side scripts in Node.js where you can enjoy the full power of Node.js including the use of NPM modules for your server-side scripts. In the previous section, we had discussed some challenges of MBaaS solutions. You can leverage Windows Azure Cloud platform for solving many challenges regarding with enterprise mobility. The entire Windows Azure platform can play a key role for working as the backend for your mobile apps where you can leverage the entire Windows Azure platform for your mobile apps. With Windows Azure, you can easily connect to your on-premises systems which is a key thing for mobile backend solutions. Another key point is that Windows Azure provides better integration with services like Active Directory, which makes Windows Azure as the de facto platform for enterprise mobility, for enterprises, who have been leveraging Microsoft ecosystem for their application and IT infrastructure. Windows Azure Mobile Services  is going to next evolution where you can expect some exciting features in near future. One area, where Windows Azure Mobile Services should definitely need an improvement, is about the default storage mechanism in which currently it is depends on SQL Server. IMHO, developers should be able to choose multiple default storage option when creating a new mobile service instance. Let’s say, there should be a different storage providers such as SQL Server storage provider and Table storage provider where developers should be able to choose their choice of storage provider when creating a new mobile services project. I have been used Windows Azure and Windows Azure Mobile Services as the backend for production apps for mobile, where it performed very well. MBaaS Over MEAP Recently, many larger enterprises has been adopted Mobile enterprise application platform (MEAP) for their mobile apps. I haven’t worked on any production MEAP solution, but I heard that developers are really struggling with MEAP in different way. The learning curve for a proprietary MEAP platform is very high. I am completely against for using larger proprietary ecosystem for mobile apps. For enterprise mobile apps, I highly recommend to use native iOS/Android/Windows Phone or HTML5  for front-end with a cloud hosted MBaaS solution as the middleware. A MBaaS service can be consumed from multiple mobile apps where REST APIs are using to integrating with enterprise backend systems. Enterprise mobility should start with exposing REST APIs on the enterprise backend systems and these REST APIs can host on Cloud where we can enjoy the power of Cloud for our services. If you are having REST APIs for your enterprise data, then you can easily build mobile frontends for multiple platforms.   You can follow me on Twitter @shijucv

  Read the article

• On Her Majesty's Secret Source Code: .NET Reflector 7 Early Access Builds Now Available

  - by Bart Read

  Dodgy Bond references aside, I'm extremely happy to be able to tell you that we've just released our first .NET Reflector 7 Early Access build. We're going to make these available over the coming weeks via the main .NET Reflector download page at: http://reflector.red-gate.com/Download.aspx Please have a play and tell us what you think in the forum we've set up. Also, please let us know if you run into any problems in the same place. The new version so far comes with numerous decompilation improvements including (after 5 years!) support for iterator blocks - i.e., the yield statement first seen in .NET 2.0. We've also done a lot of work to solidify the support for .NET 4.0. Clive's written about the work he's done to support iterator blocks in much more detail here, along with the odd problem he's encountered when dealing with compiler generated code: http://www.simple-talk.com/community/blogs/clivet/96199.aspx. On the UI front we've started what will ultimately be a rewrite of the entire front-end, albeit broken into stages over two or three major releases. The most obvious addition at the moment is tabbed browsing, which you can see in Figure 1. Figure 1. .NET Reflector's new tabbed decompilation feature. Use CTRL+Click on any item in the assembly browser tree, or any link in the source code view, to open it in a new tab. This isn't by any means finished. I'll be tying up loose ends for the next few weeks, with a major focus on performance and resource usage. .NET Reflector has historically been a largely single-threaded application which has been fine up until now but, as you might expect, the addition of browser-style tabbing has pushed this approach somewhat beyond its limit. You can see this if you refresh the assemblies list by hitting F5. This shows up another problem: we really need to make Reflector remember everything you had open before you refreshed the list, rather than just the last item you viewed - I discovered that it's always done the latter, but it used to hide all panes apart from the treeview after a Refresh, including the decompiler/disassembler window. Ultimately I've got plans to add the whole VS/Chrome/Firefox style ability to drag a tab into the middle of nowhere to spawn a new window, but I need to be mindful of the add-ins, amongst other things, so it's possible that might slip to a 7.5 or 8.0 release. You'll also notice that .NET Reflector 7 now needs .NET 3.5 or later to run. We made this jump because we wanted to offer ourselves a much better chance of adding some really cool functionality to support newer technologies, such as Silverlight and Windows Phone 7. We've also taken the opportunity to start using WPF for UI development, which has frankly been a godsend. The learning curve is practically vertical but, I kid you not, it's just a far better world. Really. Stop using WinForms. Now. Why are you still using it? I had to go back and work on an old WinForms dialog for an hour or two yesterday and it really made me wince. The point is we'll be able to move the UI in some exciting new directions that will make Reflector easier to use whilst continuing to develop its functionality without (and this is key) cluttering the interface. The 3.5 language enhancements should also enable us to be much more productive over the longer term. I know most of you have .NET Fx 3.5 or 4.0 already but, if you do need to install a new version, I'd recommend you jump straight to 4.0 because, for one thing, it's faster, and if you're starting afresh there's really no reason not to. Despite the Fx version jump the Visual Studio add-in should still work fine in Visual Studio 2005, and obviously will continue to work in Visual Studio 2008 and 2010. If you do run into problems, again, please let us know here. As before, we continue to support every edition of Visual Studio exception the Express Editions. Speaking of Visual Studio, we've also been improving the add-in. You can now open and explore decompiled code for any referenced assembly in any project in your solution. Just right-click on the reference, then click Decompile and Explore on the context menu. Reflector will pop up a progress box whilst it decompiles your assembly (Figure 2) - you can move this out of the way whilst you carry on working. Figure 2. Decompilation progress. This isn't modal so you can just move it out of the way and carry on working. Once it's done you can explore your assembly in the Reflector treeview (Figure 3), also accessible via the .NET Reflector Explore Decompiled Assemblies main menu item. Double-click on any item to open decompiled source in the Visual Studio source code view. Use right-click and Go To Definition on the source view context menu to navigate through the code. Figure 3. Using the .NET Reflector treeview within Visual Studio. Double-click on any item to open decompiled source in the source code view. There are loads of other changes and fixes that have gone in, often under the hood, which I don't have room to talk about here, and plenty more to come over the next few weeks. I'll try to keep you abreast of new functionality and changes as they go in. There are a couple of smaller things worth mentioning now though. Firstly, we've reorganised the menus and toolbar in Reflector itself to more closely mirror what you might be used to in other applications. Secondly, we've tried to make some of the functionality more discoverable. For example, you can now switch decompilation target framework version directly from the toolbar - and the default is now .NET 4.0. I think that about covers it for the moment. As I said, please use the new version, and send us your feedback. Here's that download URL again: http://reflector.red-gate.com/Download.aspx. Until next time! Technorati Tags: .net reflector,7,early access,new version,decompilation,tabbing,visual studio,software development,.net,c#,vb

  Read the article

• Code Contracts: Hiding ContractException

  - by DigiMortal

  It’s time to move on and improve my randomizer I wrote for an example of static checking of code contracts. In this posting I will modify contracts and give some explanations about pre-conditions and post-conditions. Also I will show you how to avoid ContractExceptions and how to replace them with your own exceptions. As a first thing let’s take a look at my randomizer. public class Randomizer {     public static int GetRandomFromRange(int min, int max)     {         var rnd = new Random();         return rnd.Next(min, max);     }       public static int GetRandomFromRangeContracted(int min, int max)     {         Contract.Requires(min < max, "Min must be less than max");           var rnd = new Random();         return rnd.Next(min, max);     } } We have some problems here. We need contract for method output and we also need some better exception handling mechanism. As ContractException as type is hidden from us we have to switch from ContractException to some other Exception type that we can catch. Adding post-condition Pre-conditions are contracts for method’s input interface. Read it as follows: pre-conditions make sure that all conditions for method’s successful run are met. Post-conditions are contracts for output interface of method. So, post-conditions are for output arguments and return value. My code misses the post-condition that checks return value. Return value in this case must be greater or equal to minimum value and less or equal to maximum value. To make sure that method can run only the correct value I added call to Contract.Ensures() method. public static int GetRandomFromRangeContracted(int min, int max) {     Contract.Requires(min < max, "Min must be less than max");       Contract.Ensures(         Contract.Result<int>() >= min &&         Contract.Result<int>() <= max,         "Return value is out of range"     );       var rnd = new Random();     return rnd.Next(min, max); } I think that the line I added does not need any further comments. Avoiding ContractException for input interface ContractException lives in hidden namespace and we cannot see it at design time. But it is common exception type for all contract exceptions that we do not switch over to some other type. The case of Contract.Requires() method is simple: we can tell it what kind of exception we need if something goes wrong with contract it ensures. public static int GetRandomFromRangeContracted(int min, int max) {     Contract.Requires<ArgumentOutOfRangeException>(         min < max,         "Min must be less than max"     );       Contract.Ensures(         Contract.Result<int>() >= min &&         Contract.Result<int>() <= max,         "Return value is out of range"     );       var rnd = new Random();     return rnd.Next(min, max); } Now, if we violate the input interface contract giving min value that is not less than max value we get ArgumentOutOfRangeException. Avoiding ContractException for output interface Output interface is more complex to control. We cannot give exception type there and hope that this type of exception will be thrown if something goes wrong. Instead we have to use delegate that gathers information about problem and throws the exception we expect to be thrown. From documentation you can find the following example about the delegate I mentioned. Contract.ContractFailed += (sender, e) => {     e.SetHandled();     e.SetUnwind(); // cause code to abort after event     Assert.Fail(e.FailureKind.ToString() + ":" + e.DebugMessage); }; We can use this delegate to throw the Exception. Let’s move the code to separate method too. Here is our method that uses now ContractException hiding. public static int GetRandomFromRangeContracted(int min, int max) {     Contract.Requires(min < max, "Min must be less than max");       Contract.Ensures(         Contract.Result<int>() >= min &&         Contract.Result<int>() <= max,         "Return value is out of range"     );     Contract.ContractFailed += Contract_ContractFailed;       var rnd = new Random();     return rnd.Next(min, max)+1000; } And here is the delegate that creates exception. public static void Contract_ContractFailed(object sender,     ContractFailedEventArgs e) {     e.SetHandled();     e.SetUnwind();       throw new Exception(e.FailureKind.ToString() + ":" + e.Message); } Basically we can do in this delegate whatever we like to do with output interface errors. We can even introduce our own contract exception type. As you can see later then ContractFailed event is very useful at unit testing.

  Read the article

• Cloud Based Load Testing Using TF Service &amp; VS 2013

  - by Tarun Arora [Microsoft MVP]

  Originally posted on: http://geekswithblogs.net/TarunArora/archive/2013/06/30/cloud-based-load-testing-using-tf-service-amp-vs-2013.aspx One of the new features announced as part of the Visual Studio 2013 Ultimate Preview is ‘Cloud Based Load Testing’. In this blog post I’ll walk you through, What is Cloud Based Load Testing? How have I been using this feature? – Success story! Where can you find more resources on this feature? What is Cloud Based Load Testing? It goes without saying that performance testing your application not only gives you the confidence that the application will work under heavy levels of stress but also gives you the ability to test how scalable the architecture of your application is. It is important to know how much is too much for your application! Working with various clients in the industry I have realized that the biggest barriers in Load Testing & Performance Testing adoption are, High infrastructure and administration cost that comes with this phase of testing Time taken to procure & set up the test infrastructure Finding use for this infrastructure investment after completion of testing Is cloud the answer? 100% Visual Studio Compatible Scalable and Realistic Start testing in < 2 minutes Intuitive Pay only for what you need Use existing on premise tests on cloud There are a lot of vendors out there offering Cloud Based Load Testing, to name a few, Load Storm Soasta Blaze Meter Blitz And others… The question you may want to ask is, why should you go with Microsoft’s Cloud based Load Test offering. If you are a Microsoft shop or already have investments in Microsoft technologies, you’ll see great benefit in the natural integration this offers with existing Microsoft products such as Visual Studio and Windows Azure. For example, your existing Web tests authored in Visual Studio 2010 or Visual Studio 2012 will run on the cloud without requiring any modifications what so ever. Microsoft’s cloud test rig also supports API based testing, for example, if you are building a WPF application which consumes WCF services, you can write unit tests to invoke the WCF service, these tests can be run on the cloud test rig and loaded with ‘N’ concurrent users for performance testing. If you have your assets already hosted in the Azure and possibly in the same data centre as the Cloud test rig, your Azure app will not incur a usage cost because of the generated traffic since the traffic is coming from the same data centre. The licensing or pricing information on Microsoft’s cloud based Load test service is yet to be announced, but I would expect this to be priced attractively to match the market competition.   The only additional configuration required for running load tests on Microsoft Cloud based Load Tests service is to select the Test run location as Run tests using Visual Studio Team Foundation Service, How have I been using Microsoft’s Cloud based Load Test Service? I have been part of the Microsoft Cloud Based Load Test Service advisory council for the last 7 months. This gave the opportunity to see the product shape up from concept to working solution. I was also the first person outside of Microsoft to try this offering out. This gave me the opportunity to test real world application at various clients using the Microsoft Load Test Service and provide real world feedback to the Microsoft product team. One of the most recent systems I tested using the Load Test Service has been an insurance quote generation engine. This insurance quote generation engine is,   hosted in Windows Azure expected to get quote requests from across the globe expected to handle 5 Million quote requests in a day (not clear how this load will be distributed across the day) There was no way, I could simulate such kind of load from on premise without standing up additional hardware. But Microsoft’s Cloud based Load Test service allowed me to test my key performance testing scenarios, i.e. Simulate expected Load, Endurance Testing, Threshold Testing and Testing for Latency. Simulating expected load: approach to devising a load pattern My approach to devising a load test pattern has been to run the test scenario with 1 user to figure out the response time. Then work out how many users are required to reach the target load. So, for example, to invoke 1 quote from the quote engine software takes 0.5 seconds. Now if you do the math,   1 quote request by 1 user = 0.5 seconds   quotes generated by 1 user in 24 hour = 1 * (((2 * 60) * 60) * 24) = 172,800   quotes generated by 30 users in 24 hours = 172,800 * 30 =  5,184,000 This was a very simple example, if your application requires more concurrent users to test scenario’s such as caching, etc then you can devise your own load pattern, some examples of load test patterns can be found here.  Endurance Testing To test for endurance, I loaded the quote generation engine with an expected fixed user load and ran the test for very long duration such as over 48 hours and observed the affect of the long running test on the Azure infrastructure. Currently Microsoft Load Test service does not support metrics from the machine under test. I used Azure diagnostics to begin with, but later started using Cerebrata Azure Diagnostics Manager to capture the metrics of the machine under test. Threshold Testing To figure out how much user load the application could cope with before falling on its belly, I opted to step load the quote generation engine by incrementing user load with different variations of incremental user load per minute till the application crashed out and forced an IIS reset. Testing for Latency Currently the Microsoft Load Test service does not support generating geographically distributed load, I however, deployed the insurance quote generation engine in different Azure data centres and ran the same set of performance tests to measure for latency. Because I could compare load test results from different runs by exporting the results to excel (this feature is provided out of the box right from Visual Studio 2010) I could see the different in response times. More resources on Microsoft Cloud based Load Test Service A few important links to get you started, Download Visual Studio Ultimate 2013 Preview Getting started guide for load testing using Team Foundation Service Troubleshooting guide for FAQs and known issues Team Foundation Service forum for questions and support Detailed demo and presentation (link to Tech-Ed session recording) Detailed demo and presentation (link to Build session recording) There a few limits on the usage of Microsoft Cloud based Load Test service that you can read about here. If you have any feedback on Microsoft Cloud based Load Test service, feel free to share it with the product team via the Visual Studio User Voice forum. I hope you found this useful. Thank you for taking the time out and reading this blog post. If you enjoyed the post, remember to subscribe to http://feeds.feedburner.com/TarunArora. Stay tuned!

  Read the article

• At the Java DEMOgrounds - JavaFX

  - by Janice J. Heiss

  JavaFX has made rapid progress in the last year, as is evidenced by the wealth of demos on display. A few questions appear to be prominent in the minds of JavaFX enthusiasts. Here are some questions with answers provided by Oracle’s JavaFX team.When will the rest of the JavaFX code be available in open source?Oracle has started to open source JavaFX. The existing platform code will finish being committed to OpenJFX by the end of the year.Why should I use JavaFX instead of HTML5?We see JavaFX as complementary to HTML5, and most companies we talk to react positively once they understand how they can benefit from a hybrid solution. As most HTML5 developers will tell you, the biggest obstacle to deploying HTML5 applications is fragmentation. JavaFX offers a convenient way to render HTML and JavaScript within its WebView component, which provides the same level of quality and features across Windows, Mac, and Linux. Additionally, JavaScript in WebView can make calls into the Java code, and vice versa, allowing developers to tap into the best of both worlds.What is the market penetration of JavaFX? It is currently limited, as we've just made available JavaFX on Mac and Linux in August, but we expect JavaFX to be present on millions of desktop-type systems now that JavaFX is included as part of the JRE. We have also significantly lowered the level of effort required to deploy an application bundling the JRE and JavaFX runtime libraries. Finally, we are seeing a lot of interest by companies operating in the embedded market, who have found it hard to develop compelling UIs with existing technologies.Below are summaries of JavaFX Demos on display at JavaOne 2012:JavaFX EnsembleEnsemble is a collection of over 100 JavaFX samples packaged as a JavaFX application. This demo is especially useful to those new to JavaFX, or those not familiar with its latest features (e.g. canvas, color picker). Ensemble is the reference for getting familiar with JavaFX functionality. Each sample can be run from within Ensemble, and the API for each sample, as well as the source code are available alongside the sample.The samples source code can be saved as a NetBeans project for convenience purposes, or can be copied as is in any other Java IDE. The version of Ensemble shown is packaged as a native Windows application, including the JRE and JavaFX libraries. It was created with the JavaFX packager, which provides multiple packaging options, and frees developers from the cumbersome and error-prone process of packaging a Java application.FX Experience ToolsFX Experience Tools is a JavaFX application that provides different utilities to create new skins for your JavaFX applications. One of the most powerful features of JavaFX is the ability to skin applications via CSS. Since not all Java developers are familiar with CSS, these utilities are a great starting point to create custom skins. JavaFX allows developers to easily customize the look and feel of their applications through CSS. FX Experience Tools makes it easy to create new themes for JavaFX applications, even if you are not familiar with CSS. FX Experience Tools is a JavaFX application packaged as a native application including the JRE and JavaFX runtime libraries. FX Experience tools shows how this type of deployment simplifies the packaging of Java applications without requiring developers to master the intricacies of Java application packaging. The download site for FX Experience Tools is http://fxexperience.com/2012/03/announcing-fx-experience-tools/ JavaFX Scene BuilderJavaFX Scene Builder is a visual layout tool that lets users quickly design the UI of your JavaFX application, without coding. Users can drag and drop UI components, modify their properties, apply style sheets, and the FXML code they create for the layout is automatically generated in the background. The result is an FXML file that can then be combined with a Java project by binding the UI to the application’s logic. Developers can easily create user interfaces for their application, as well as separate the application’s UI from the application logic for easier maintenance. Attendees can get this app by going to javafx.com and checking the link at top of the “Overview” page.Scene Builder allows developers to easily layout JavaFX UI controls, charts, shapes, and containers, so that you can quickly prototype user interfaces. It generates FXML, an XML-based markup language that enables users to define an application’s user interface, separately from the application logic. Scene Builder can be used in combination with any Java IDE, but is more tightly integrated with NetBeans IDE. It is written as a JavaFX application, with native desktop integration on Windows and Mac OS X. It’s a perfect example of a JavaFX application packages as a native application.Scene Builder is available for your preferred development platform. Besides the GA release on Windows and Mac, a Developer Preview of Scene Builder for Linux has just been made available.Scenic ViewScenic View is a tool that can be used to understand the current state of your application UI, and to also easily manipulate properties of the scenegraph without having to keep editing your code. Creating UIs is a complex process, and it can be hard and tedious detecting these issues, editing the code, and then compiling it to test the app again. Scenic View is a great diagnostics tool that helps developers identify these issues and correct them at runtime.Attendees can get Scenic View by going to javafx.com, selecting the “Community” tab, and clicking the link under the “Third Party Tools and Utilities” section.Scenic View allows developers to easily examine the state of a JavaFX application scenegraph while the application is running. Some of the latest features added to Scenic View include event monitoring, javadoc browsing, and contextual menus. The download site for Scenic View is available here: http://fxexperience.com/scenic-view/ Conference TourConference Tour is an application that lets users discover some of the major Java conferences throughout the world. The Conference Tour application shows how simple it is to mix JavaFX and HTML5 into a single, interactive application. Attendees get Conference Tour here.JavaFX includes a Web engine based on Webkit that provides a consistent web interface to render HTML5 across operating systems, within a JavaFX application. JavaFX features a bi-directional bridge that allows Java APIs to call JavaScript within WebView, or allows JavaScript to make calls to Java APIs. This allows developers to leverage the best of both worlds.Java EE developers can take advantage of WebView and the JavaScript-Java bridge to allow their HTML clients to seamlessly bypass Web browser’s sandbox to access native system resources, providing a richer user experience.FXMediaPlayerFXMediaPlayer is an application that lets developers check different media functionality in JavaFX, such as synthesizer or support for HTTP Live Streaming (HLS). This demo shows how developers can embed video content in their Java applications. JavaFX leverages the underlying video (e.g., H.264) and audio (e.g., AAC) codecs on the user’s computer. JavaFX APIs allow developers to interact with the video content (e.g. play/pause, or programmable markers). Some of the latest media features introduced in JavaFX 2.2 include HTTP Live Streaming (HLS). Obviously there is a lot for JavaFX enthusiasts to chew on!

  Read the article

• How to get SQL Railroad Diagrams from MSDN BNF syntax notation.

  - by Phil Factor

  pre {margin-bottom:.0001pt; font-size:8.0pt; font-family:"Courier New"; margin-left: 0cm; margin-right: 0cm; margin-top: 0cm; } On SQL Server Books-On-Line, in the Transact-SQL Reference (database Engine), every SQL Statement has its syntax represented in  ‘Backus–Naur Form’ notation (BNF)  syntax. For a programmer in a hurry, this should be ideal because It is the only quick way to understand and appreciate all the permutations of the syntax. It is a great feature once you get your eye in. It isn’t the only way to get the information;  You can, of course, reverse-engineer an understanding of the syntax from the examples, but your understanding won’t be complete, and you’ll have wasted time doing it. BNF is a good start in representing the syntax:  Oracle and SQLite go one step further, and have proper railroad diagrams for their syntax, which is a far more accessible way of doing it. There are three problems with the BNF on MSDN. Firstly, it is isn’t a standard version of  BNF, but an ancient fork from EBNF, inherited from Sybase. Secondly, it is excruciatingly difficult to understand, and thirdly it has a number of syntactic and semantic errors. The page describing DML triggers, for example, currently has the absurd BNF error that makes it state that all statements in the body of the trigger must be separated by commas.  There are a few other detail problems too. Here is the offending syntax for a DML trigger, pasted from MSDN. Trigger on an INSERT, UPDATE, or DELETE statement to a table or view (DML Trigger) CREATE TRIGGER [ schema_name . ]trigger_name ON { table | view } [ WITH <dml_trigger_option> [ ,...n ] ] { FOR | AFTER | INSTEAD OF } { [ INSERT ] [ , ] [ UPDATE ] [ , ] [ DELETE ] } [ NOT FOR REPLICATION ] AS { sql_statement [ ; ] [ ,...n ] | EXTERNAL NAME <method specifier [ ; ] > }   <dml_trigger_option> ::=     [ ENCRYPTION ]     [ EXECUTE AS Clause ]   <method_specifier> ::=  This should, of course, be /* Trigger on an INSERT, UPDATE, or DELETE statement to a table or view (DML Trigger) */ CREATE TRIGGER [ schema_name . ]trigger_name ON { table | view } [ WITH <dml_trigger_option> [ ,...n ] ] { FOR | AFTER | INSTEAD OF } { [ INSERT ] [ , ] [ UPDATE ] [ , ] [ DELETE ] } [ NOT FOR REPLICATION ] AS { {sql_statement [ ; ]} [ ...n ] | EXTERNAL NAME <method_specifier> [ ; ] }   <dml_trigger_option> ::=     [ ENCRYPTION ]     [ EXECUTE AS CLAUSE ]   <method_specifier> ::=     assembly_name.class_name.method_name I’d love to tell Microsoft when I spot errors like this so they can correct them but I can’t. Obviously, there is a mechanism on MSDN to get errors corrected by using comments, but that doesn’t work for me (*Error occurred while saving your data.”), and when I report that the comment system doesn’t work to MSDN, I get no reply. I’ve been trying to create railroad diagrams for all the important SQL Server SQL statements, as good as you’d find for Oracle, and have so far published the CREATE TABLE and ALTER TABLE railroad diagrams based on the BNF. Although I’ve been aware of them, I’ve never realised until recently how many errors there are. Then, Colin Daley created a translator for the SQL Server dialect of  BNF which outputs standard EBNF notation used by the W3C. The example MSDN BNF for the trigger would be rendered as … /* Trigger on an INSERT, UPDATE, or DELETE statement to a table or view (DML Trigger) */ create_trigger ::= 'CREATE TRIGGER' ( schema_name '.' ) ? trigger_name 'ON' ( table | view ) ( 'WITH' dml_trigger_option ( ',' dml_trigger_option ) * ) ? ( 'FOR' | 'AFTER' | 'INSTEAD OF' ) ( ( 'INSERT' ) ? ( ',' ) ? ( 'UPDATE' ) ? ( ',' ) ? ( 'DELETE' ) ? ) ( 'NOT FOR REPLICATION' ) ? 'AS' ( ( sql_statement ( ';' ) ? ) + | 'EXTERNAL NAME' method_specifier ( ';' ) ? )   dml_trigger_option ::= ( 'ENCRYPTION' ) ? ( 'EXECUTE AS CLAUSE' ) ?   method_specifier ::= assembly_name '.' class_name '.' method_name Colin’s intention was to allow anyone to paste SQL Server’s BNF notation into his website-based parser, and from this generate classic railroad diagrams via Gunther Rademacher's Railroad Diagram Generator.  Colin's application does this for you: you're not aware that you are moving to a different site.  Because Colin's 'translator' it is a parser, it will pick up syntax errors. Once you’ve fixed the syntax errors, you will get the syntax in the form of a human-readable railroad diagram and, in this form, the semantic mistakes become flamingly obvious. Gunter’s Railroad Diagram Generator is brilliant. To be able, after correcting the MSDN dialect of BNF, to generate a standard EBNF, and from thence to create railroad diagrams for SQL Server’s syntax that are as good as Oracle’s, is a great boon, and many thanks to Colin for the idea. Here is the result of the W3C EBNF from Colin’s application then being run through the Railroad diagram generator. create_trigger: dml_trigger_option: method_specifier:   Now that’s much better, you’ll agree. This is pretty easy to understand, and at this point any error is immediately obvious. This should be seriously useful, and it is to me. However  there is that snag. The BNF is generally incorrect, and you can’t expect the average visitor to mess about with it. The answer is, of course, to correct the BNF on MSDN and maybe even add railroad diagrams for the syntax. Stop giggling! I agree it won’t happen. In the meantime, we need to collaboratively store and publish these corrected syntaxes ourselves as we do them. How? GitHub?  SQL Server Central?  Simple-Talk? What should those of us who use the system  do with our corrected EBNF so that anyone can use them without hassle?

  Read the article

• Run Your Tests With Any NUnit Version

  - by Alois Kraus

  I always thought that the NUnit test runners and the test assemblies need to reference the same NUnit.Framework version. I wanted to be able to run my test assemblies with the newest GUI runner (currently 2.5.3). Ok so all I need to do is to reference both NUnit versions the newest one and the official for the current project. There is a nice article form Kent Bogart online how to reference the same assembly multiple times with different versions. The magic works by referencing one NUnit assembly with an alias which does prefix all types inside it. Then I could decorate my tests with the TestFixture and Test attribute from both NUnit versions and everything worked fine except that this was ugly. After playing a little bit around to make it simpler I found that I did not need to reference both NUnit.Framework assemblies. The test runners do not require the TestFixture and Test attribute in their specific version. That is really neat since the test runners are instructed by attributes what to do in a declarative way there is really no need to tie the runners to a specific version. At its core NUnit has this little method hidden to find matching TestFixtures and Tests   public bool CanBuildFrom(Type type) {     if (!(!type.IsAbstract || type.IsSealed))     {         return false;     }     return (((Reflect.HasAttribute(type,           "NUnit.Framework.TestFixtureAttribute", true) ||               Reflect.HasMethodWithAttribute(type, "NUnit.Framework.TestAttribute"       , true)) ||               Reflect.HasMethodWithAttribute(type, "NUnit.Framework.TestCaseAttribute"   , true)) ||               Reflect.HasMethodWithAttribute(type, "NUnit.Framework.TheoryAttribute"     , true)); } That is versioning and backwards compatibility at its best. I tell NUnit what to do by decorating my tests classes with NUnit Attributes and the runner executes my intent without the need to bind me to a specific version. The contract between NUnit versions is actually a bit more complex (think of AssertExceptions) but this is also handled nicely by using not the concrete type but simply to check for the catched exception type by string. What can we learn from this? Versioning can be easy if the contract is small and the users of your library use it in a declarative way (Attributes). Everything beyond it will force you to reference several versions of the same assembly with all its consequences. Type equality is lost between versions so none of your casts will work. That means that you cannot simply use IBigInterface in two versions. You will need a wrapper to call the correct versioned one. To get out of this mess you can use one (and only one) version agnostic driver to encapsulate your business logic from the concrete versions. This is of course more work but as NUnit shows it can be easy. Simplicity is therefore not a nice thing to have but also requirement number one if you intend to make things more complex in version two and want to support any version (older and newer). Any interaction model above easy will not be maintainable. There are different approached to versioning. Below are my own personal observations how versioning works within the  .NET Framwork and NUnit.   Versioning Models 1. Bug Fixing and New Isolated Features When you only need to fix bugs there is no need to break anything. This is especially true when you have a big API surface. Microsoft did this with the .NET Framework 3.0 which did leave the CLR as is but delivered new assemblies for the features WPF, WCF and Windows Workflow Foundations. Their basic model was that the .NET 2.0 assemblies were declared as red assemblies which must not change (well mostly but each change was carefully reviewed to minimize the risk of breaking changes as much as possible) whereas the new green assemblies of .NET 3,3.5 did not have such obligations since they did implement new unrelated features which did not have any impact on the red assemblies. This is versioning strategy aimed at maximum compatibility and the delivery of new unrelated features. If you have a big API surface you should strive hard to do the same or you will break your customers code with every release. 2. New Breaking Features There are times when really new things need to be added to an existing product. The .NET Framework 4.0 did change the CLR in many ways which caused subtle different behavior although the API´s remained largely unchanged. Sometimes it is possible to simply recompile an application to make it work (e.g. changed method signature void Func() –> bool Func()) but behavioral changes need much more thought and cannot be automated. To minimize the impact .NET 2.0,3.0,3.5 applications will not automatically use the .NET 4.0 runtime when installed but they will keep using the “old” one. What is interesting is that a side by side execution model of both CLR versions (2 and 4) within one process is possible. Key to success was total isolation. You will have 2 GCs, 2 JIT compilers, 2 finalizer threads within one process. The two .NET runtimes cannot talk  (except via the usual IPC mechanisms) to each other. Both runtimes share nothing and run independently within the same process. This enables Explorer plugins written for the CLR 2.0 to work even when a CLR 4 plugin is already running inside the Explorer process. The price for isolation is an increased memory footprint because everything is loaded and running two times.   3. New Non Breaking Features It really depends where you break things. NUnit has evolved and many different Assert, Expect… methods have been added. These changes are all localized in the NUnit.Framework assembly which can be easily extended. As long as the test execution contract (TestFixture, Test, AssertException) remains stable it is possible to write test executors which can run tests written for NUnit 10 because the execution contract has not changed. It is possible to write software which executes other components in a version independent way but this is only feasible if the interaction model is relatively simple.   Versioning software is hard and it looks like it will remain hard since you suddenly work in a severely constrained environment when you try to innovate and to keep everything backwards compatible at the same time. These are contradicting goals and do not play well together. The easiest way out of this is to carefully watch what your customers are doing with your software. Minimizing the impact is much easier when you do not need to guess how many people will be broken when this or that is removed.

  Read the article

• Making Money from your SQL Server Blog

  - by Bill Graziano

  My SQL Server blog reading list is around one hundred blogs.  Many people are writing great content and generating lots of page views.  I see some of them running Google AdSense and trying to make a little money off their traffic.  If you want to earn some some extra money from what you’ve written there are a couple of options.  And one new option that I’m announcing here. Background Internet advertising is sold based on a few different pricing schemes.  Flat Fee.  You offer either all your impressions (page views) or some percentage of your impressions in exchange for a flat monthly fee.  CPM or cost per thousand impressions.  If the quoted price is $2 CPM you’ll get $2 for every 1,000 times the ad is displayed.  While you might think the “M” means millions, the “M” in CPM is the roman numeral for 1,000. CPC or cost per click.  This is also called PPC or pay per click.  In this method you get paid based on how many clicks there are on the ad.  CPA or cost per action.  In this method you get paid based on an action that occurs on the advertisers site after they click on the ad.  This is typically some type of sign up form.  This is how most affiliate programs work. Darren Rowse at ProBlogger has been writing about blogging and making money off blogs for years.  He has a good introduction to making money on your blog in his “Making Money” section.  If you’re interested in learning more he has a post up titled How to Make More Money From Your Blog in the New Year that links to many of his best posts on the subject. Google AdSense This is the most common method for people earning money from their blogging.  It’s easy to setup and administer.  You tell AdSense what size ads you’d like to run and it gives you a little piece of JavaScript to put on your site.  AdSense quickly learns the topics you write about and displays ads that are appropriate for your site.  I typically see ads for hosting, SQL Server tools and developer tools running in AdSense slots.  AdSense pays on a CPC model.  If you translate that back to CPM pricing you’ll see rates from $0.50 to $1.00 CPM. Amazon While you might not make much money writing books it’s now possible to make even less helping Amazon sell them.  You can sign up for an Amazon affiliate program.  Each time you send Amazon a link and someone buys the book you get a cut of that sale.  This is the CPA model from above.  Amazon can help you build some pretty nice “stores”.  Here’s the SQL Server bookstore I built for SQLTeam.com.  If you’re just putting in a page with books like I’ve done on SQLTeam you should keep your expectations low.  If you’re writing book reviews of suggesting books on your blog it really does make sense to setup an Amazon affiliate link.  People are much more likely to buy a book based on a review from a trusted source.  I always try to buy through a referral link if there is one. Amazon pays about 4% of the price as a referral fee.  You also get credit for anything else they buy while on the site.  I recently had someone buy an iPod nano with their SQL Server book making me an extra $5.60 richer!  Estimating how much you can make is difficult though.  How much attention you draw to the links and book reviews can dramatically affect the earnings. Private Ad Sales This is the hardest but potentially most lucrative option.  You sell advertising directly to companies that want to sell things to your readers.  Typically this would be SQL Server tool vendors, hosting companies or anyone else that wants to make money off database administrators.  This is also the most difficult to do.  You’ll need the contacts at the companies and enough page views to make it worth their while.  You’ll also need software to track the page views and clicks, geo-target your ads and smooth out the impressions.  Your earnings are based on whatever you can negotiate with the companies. SQL Server Ad Network For the last couple of years I’ve run any extra ads that I sold on the SQLTeam Weblogs.  You can see an example of that on Mladen’s blog.  The ad in the upper right corner is one that I’m running for him.  (Note: Many of the ads I’m running are geo-targeted to only appear in English speaking countries.  You may see a different set of ads outside the US, Canada and the UK.  You can also see he has a couple of Google ads on his blog.)  When I run ads on his blog I split the advertising revenue with him.  They make a little and I make a little. I recently started to expand this and sell advertising specifically to run on SQL Server-related blogs.  I’m also starting to run ads on non-SQLTeam blogs.  The only way I can sell more advertising is to have more blogs to run it on.  And that’s where you come in. I’ve created a SQL Server advertising network.  I handle all the ad sales and provide the technology to serve the ads.  I handle collections and payments back to you.  You get paid at the end of each month regardless of when (or if) the advertiser actually pays.  All you need to do is add a small piece of JavaScript to your site to display the ads. If you’re writing about SQL Server and interested in earning a little money for your site I’d like to talk to you.  You can use the Contact Us page on SQLTeam.com to reach me.  Running advertising on your blog isn’t for everyone.  If you’re concerned about what advertisers might think about certain posts then you might not be a good fit.  For the most part this isn’t an issue.  You’ll also need to have a PayPal account to receive payments.  You probably won’t get rich doing this.  But you can earn extra cash on the side for doing what you would do anyway.  I do know that people have earned enough to buy themselves a nice laptop doing this. My initial target is blogs with more than 10,000 page views per month.  I expect to pay two to three times what Google pays.  If you have less than 10,000 page views per month but are still interested I’d still like to hear from you.  I may not be able to sign up smaller blogs right away but we’ll get the process started.  If you’re unsure about your traffic Google Analytics is a free tool that provides great reporting on traffic, popular posts and how people find your blog.  If you have any questions or are just curious drop me a line and I’ll try to answer your questions.

  Read the article

• C#/.NET Little Pitfalls: The Dangers of Casting Boxed Values

  - by James Michael Hare

  Starting a new series to parallel the Little Wonders series.  In this series, I will examine some of the small pitfalls that can occasionally trip up developers. Introduction: Of Casts and Conversions What happens when we try to assign from an int and a double and vice-versa? 1: double pi = 3.14; 2: int theAnswer = 42; 3:  4: // implicit widening conversion, compiles! 5: double doubleAnswer = theAnswer; 6:  7: // implicit narrowing conversion, compiler error! 8: int intPi = pi; As you can see from the comments above, a conversion from a value type where there is no potential data loss is can be done with an implicit conversion.  However, when converting from one value type to another may result in a loss of data, you must make the conversion explicit so the compiler knows you accept this risk.  That is why the conversion from double to int will not compile with an implicit conversion, we can make the conversion explicit by adding a cast: 1: // explicit narrowing conversion using a cast, compiler 2: // succeeds, but results may have data loss: 3: int intPi = (int)pi; So for value types, the conversions (implicit and explicit) both convert the original value to a new value of the given type.  With widening and narrowing references, however, this is not the case.  Converting reference types is a bit different from converting value types.  First of all when you perform a widening or narrowing you don’t really convert the instance of the object, you just convert the reference itself to the wider or narrower reference type, but both the original and new reference type both refer back to the same object. Secondly, widening and narrowing for reference types refers the going down and up the class hierarchy instead of referring to precision as in value types.  That is, a narrowing conversion for a reference type means you are going down the class hierarchy (for example from Shape to Square) whereas a widening conversion means you are going up the class hierarchy (from Square to Shape).  1: var square = new Square(); 2:  3: // implicitly convers because all squares are shapes 4: // (that is, all subclasses can be referenced by a superclass reference) 5: Shape myShape = square; 6:  7: // implicit conversion not possible, not all shapes are squares! 8: // (that is, not all superclasses can be referenced by a subclass reference) 9: Square mySquare = (Square) myShape; So we had to cast the Shape back to Square because at that point the compiler has no way of knowing until runtime whether the Shape in question is truly a Square.  But, because the compiler knows that it’s possible for a Shape to be a Square, it will compile.  However, if the object referenced by myShape is not truly a Square at runtime, you will get an invalid cast exception. Of course, there are other forms of conversions as well such as user-specified conversions and helper class conversions which are beyond the scope of this post.  The main thing we want to focus on is this seemingly innocuous casting method of widening and narrowing conversions that we come to depend on every day and, in some cases, can bite us if we don’t fully understand what is going on!  The Pitfall: Conversions on Boxed Value Types Can Fail What if you saw the following code and – knowing nothing else – you were asked if it was legal or not, what would you think: 1: // assuming x is defined above this and this 2: // assignment is syntactically legal. 3: x = 3.14; 4:  5: // convert 3.14 to int. 6: int truncated = (int)x; You may think that since x is obviously a double (can’t be a float) because 3.14 is a double literal, but this is inaccurate.  Our x could also be dynamic and this would work as well, or there could be user-defined conversions in play.  But there is another, even simpler option that can often bite us: what if x is object? 1: object x; 2:  3: x = 3.14; 4:  5: int truncated = (int) x; On the surface, this seems fine.  We have a double and we place it into an object which can be done implicitly through boxing (no cast) because all types inherit from object.  Then we cast it to int.  This theoretically should be possible because we know we can explicitly convert a double to an int through a conversion process which involves truncation. But here’s the pitfall: when casting an object to another type, we are casting a reference type, not a value type!  This means that it will attempt to see at runtime if the value boxed and referred to by x is of type int or derived from type int.  Since it obviously isn’t (it’s a double after all) we get an invalid cast exception! Now, you may say this looks awfully contrived, but in truth we can run into this a lot if we’re not careful.  Consider using an IDataReader to read from a database, and then attempting to select a result row of a particular column type: 1: using (var connection = new SqlConnection("some connection string")) 2: using (var command = new SqlCommand("select * from employee", connection)) 3: using (var reader = command.ExecuteReader()) 4: { 5: while (reader.Read()) 6: { 7: // if the salary is not an int32 in the SQL database, this is an error! 8: // doesn't matter if short, long, double, float, reader [] returns object! 9: total += (int) reader["annual_salary"]; 10: } 11: } Notice that since the reader indexer returns object, if we attempt to convert using a cast to a type, we have to make darn sure we use the true, actual type or this will fail!  If the SQL database column is a double, float, short, etc this will fail at runtime with an invalid cast exception because it attempts to convert the object reference! So, how do you get around this?  There are two ways, you could first cast the object to its actual type (double), and then do a narrowing cast to on the value to int.  Or you could use a helper class like Convert which analyzes the actual run-time type and will perform a conversion as long as the type implements IConvertible. 1: object x; 2:  3: x = 3.14; 4:  5: // if you want to cast, must cast out of object to double, then 6: // cast convert. 7: int truncated = (int)(double) x; 8:  9: // or you can call a helper class like Convert which examines runtime 10: // type of the value being converted 11: int anotherTruncated = Convert.ToInt32(x); Summary You should always be careful when performing a conversion cast from values boxed in object that you are actually casting to the true type (or a sub-type). Since casting from object is a widening of the reference, be careful that you either know the exact, explicit type you expect to be held in the object, or instead avoid the cast and use a helper class to perform a safe conversion to the type you desire. Technorati Tags: C#,.NET,Pitfalls,Little Pitfalls,BlackRabbitCoder

  Read the article

< Previous Page | 177 178 179 180 181 182 183 184 185 186 187 188  | Next Page >