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How to implement an ItemsControl3D which can use templates of Visual3D?

- by Christo

I'm looking for something like a ContainerUIElement3D which supports the ItemsSource property and an ItemTemplate property which I can use within a Viewport3D. My aim is to be able to write something like: <ItemsControl3D ItemsSource="{Binding Path=MyItems}"> <ItemsControl3D.ItemTemplate> <DataTemplate3D>  <DataTemplate3D> </ItemsControl3D.ItemTemplate> </ItemsControl3D> I'm looking for tips on how to implement this. The first tricky part is to create a DataTemplate3D which can construct the Visual3D needed to add to the ItemsControl3D. I've been using .NET reflector to browse through the implementation of ItemsControl and DataTemplate, but I soon realised that I don't have a deep enough understanding and enough time to come up with a solution on my own.

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MVVM where does the code to load the data belong?

- by cody

As I wrap my head around the mvvm thing, the view is the view, and the viewmodel is 'a modal of a view' and the model are the entities we are dealing with (or at least that is my understanding). But I'm unclear as to what and when the model entities are populated. So for example: Lets say I have app that needs to create a new record in a DB. And that record should have default values to start with. Who is responsible for the new record, and getting the default values. Does this have anything to do with MVVM or is that part of a data access layer? Who calls the the viewmodel? Or for existing records when\where are the records retrieved? And saved if altered? Thanks

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Android: stack management for views in a tab?

- by wei

I see some answers here prefer views over activities as contents of tabs. Correct me if I am wrong. My understanding is that by switching out views, it's possible to keep the navigation flow inside a tab (more user friendly, I think). But I wonder how to manage the view stack then in case of the back button events. Also this could cause one giant Activity with large amount of views, which might not be good. So I wish to know why exactly views as contents is preferred before I change my current application to this. Thanks,

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why is there different id syntax in the Android docs?

- by darren

This page in the Android documentation defines an element id as follows: <TextView android:id="@+id/label" android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="Type here:" /> However this page defines it as: <EditText id="text" xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" android:textColor="@color/opaque_red" android:text="Hello, World!" /> I thought I had a decent understanding of what was going on until I saw this second example. In the first case, you need the + character so that id 'label' is added to the R file, correct? In the second case, would the EditText's id not be added to the R file because it does not contain the + character? Also, the second example does not include the android namespace on the id. Does having or not having the Android namespace affect whether that id will be added to the R file? Thanks for any clarification.

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Haskell: Pattern Matching with Lists

- by user1670032

I'm trying to make a function that takes in a list, and if one of the elements is negative, then any elements in that list that are equal to its positive counterpart should be changed to 0. Eg, if there is a -2 in a list, then all 2's in that list should be changed to 0. Any ideas why it only works for some cases and not others? I'm not understanding why this is, I've looked it over several times. changeToZero [] = [] changeToZero [x] = [x] changeToZero (x:zs:y:ws) | (x < 0) && ((-1)*(x) == y) = x : zs : 0 : changeToZero ws changeToZero (x:xs) = x : changeToZero xs *Main changeToZero [-1,1,-2,2,-3,3] [-1,1,-2,2,-3,3] *Main changeToZero [-2,1,2,3] [-2,1,0,3] *Main changeToZero [-2,1,2,3,2] [-2,1,0,3,2] *Main changeToZero [1,-2,2,2,1] [1,-2,2,0,1]

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C# regex: negative lookahead fails with the single line option

- by Sylverdrag

I am trying to figure out why a regex with negative look ahead fails when the "single line" option is turned on. Example (simplified): <source>Test 1</source> <source>Test 2</source> <target>Result 2</target> <source>Test 3</source> This: <source>(?!.*<source>)(.*?)</source>(?!\s*<target) will fail if the single line option is on, and will work if the single line option is off. For instance, this works (disables the single line option): (?-s:<source>(?!.*<source>)(.*?)</source>(?!\s*<target)) My understanding is that the single line mode simply allows the dot "." to match new lines, and I don't see why it would affect the expression above. Can anyone explain what I am missing here?

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Why make anything internal?

- by c-charp N00b

I don't really see the point of making methods or classes internal. In my very limited understanding, all it does is make working with your code very difficult for other programmers. Say I write Big_Important_Class for Project A and make said class internal. Then Bob, working on Project B needs to use my class to have project B work with Project A, but since its internal he can't. As of now this is the only thing I have seen internals do, make things really complicated for the guy working on Project B. I know there has to be a good reason to use internals, but I don't see any. Could someone please explain how they can be a good thing?

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Assigning a variable of a struct that contains an instance of a class to another variable

- by xport

In my understanding, assigning a variable of a struct to another variable of the same type will make a copy. But this rule seems broken as shown on the following figure. Could you explain why this happened? using System; namespace ReferenceInValue { class Inner { public int data; public Inner(int data) { this.data = data; } } struct Outer { public Inner inner; public Outer(int data) { this.inner = new Inner(data); } } class Program { static void Main(string[] args) { Outer p1 = new Outer(1); Outer p2 = p1; Console.WriteLine("p1:{0}, p2:{1}", p1.inner.data, p2.inner.data); p1.inner.data = 2; Console.WriteLine("p1:{0}, p2:{1}", p1.inner.data, p2.inner.data); p2.inner.data = 3; Console.WriteLine("p1:{0}, p2:{1}", p1.inner.data, p2.inner.data); Console.ReadKey(); } } }

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ARC, worth it or not?

- by MSK

When I moved to Objective C (iOS) from C++ (and little Java) I had hard time understanding memory management in iOS. But now all this seems natural and I know retain, autorelease, copy and release stuff. After reading about ARC, I am wondering is there more benefits of using ARC or it is just that you dont have to worry about memory management. Before moving to ARC I wanted to know how worth is moving to ARC. XCode has "Convert to Objective C ARC" menu. Is the conversion is that simple (nothing to worry about)? Does it help me in reducing my apps memory foot-print, memory leaks etc (somehow ?) Does it has much testing impact on my apps ? What are non-obvious advantages? Any Disadvantage os moving to it?

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Including C header file with lots of global variables

- by Costi

I have an include file with 100+ global variables. It's being used in a library, but some programs that I'm linking the lib to also need to access the globals. The way it was built: // In one library .c file #define Extern // In the programs that use the globals #define Extern extern // In the .h file Extern int a,b,c; I had a hard time understanding why the original programmer did that so I removed that define Extern stuff. Now I think I understand the thing about TU with the help of stackoverflow: 1, 2, 3. Now I understand that I should define the global variables in one .c file in the library and use extern in the .h file. The problem is that I don't want to duplicate code. Should I go back to that #define Extern voodoo?

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Improving the join of two wave file?

- by kaki

I have written a code for joining two wave files.It works fine when i am joining larger segments but as i need to join very small segments the clarity is not good. I have learned that the signal processing technique such a windowed join can be used to improve the joining of file. y[n] = w[n]s[n] Multiply value of signal at sample number n by the value of a windowing function hamming window w[n]= .54 - .46*cos(2*Pi*n)/L 0 I am not understanding how to get the value to signal at sample n and how to implement this?? the code i am using for joining is import wave m=['C:/begpython/S0001_0002.wav', 'C:/begpython/S0001_0001.wav'] i=1 a=m[i] infiles = [a, "C:/begpython/S0001_0002.wav", a] outfile = "C:/begpython/S0001_00367.wav" data= [] data1=[] for infile in infiles: w = wave.open(infile, 'rb') data1=[w.getnframes] data.append( [w.getparams(), w.readframes(w.getnframes())] ) #data1 = [ord(character) for character in data1] #print data1 #data1 = ''.join(chr(character) for character in data1) w.close() output = wave.open(outfile, 'wb') output.setparams(data[0][0]) output.writeframes(data[0][1]) output.writeframes(data[1][1]) output.writeframes(data[2][1]) output.close()

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How do I configure WinCE to use wildcard SSL certificates?

- by Robin M

Our Windows CE 5.0 application has a problem with our wildcard SSL certificate (*.domain.com) - it won't accept it as valid. I understand that Windows Mobile 6.0 has support for wildcard certificates (earlier versions don't) and that is built on WinCE 5 which suggests it should be possible to change WinCE 5 to accept wildcard certificates (EDIT - apparently this shows my limited understanding of the environment and isn't a valid presumption!). Can anyone suggest how we go about this? The change needs to be programmatic so that we can roll it out to hundreds of existing clients. Help!

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Lifetime of javacript variables.

- by The Machine

What is the lifetime of a variable in javascript, declared with "var". I am sure, it is definitely not according to expectation. <script> function(){ var a; var fun=function(){ // a is accessed and modified } }(); </script> Here how and when does javascript garbage collect the variable a? Since 'a' is a part of the closure of the inner function, it ideally should never get garbage collected, since the inner function 'fun', may be passed as a reference to an external context.So 'fun' should still be able to access 'a', from the external context. If my understanding is correct, how does garbage collection happen then, and how does it ensure to have enough memory space, since keeping all variables in memory until the execution of the program might not be tenable ?

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Perl : localtime with print

- by kiruthika

Hi all, I have used the following statements to get the current time. print "$query executed successfully at ",localtime; print "$query executed successfully at ",(localtime); print "$query executed successfully at ".(localtime); Output executed successfully at 355516731103960 executed successfully at 355516731103960 executed successfully at Wed Apr 7 16:55:35 2010 The first two statements are not printing the current time in a date format. Third statement only giving the correct output in a date format. My understanding is the first one is returning a value in scalar context,so it is returning numbers. Then in the second print I used localtime in list context only,why it's also giving number output.

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Cant see images on print preview

- by Viren

I been ask to lay a page where user can click on print option to print that page All the code is hooked up the print command works with one exception the images on web page arent getting reflected in print preview . there isnt any special stylesheet applied for printing to be specific the page has no stylesheet The code for print is given below <a href="javascript:window.print()">Print</a> Attaching the screenshot of the page And the print preview page for better understanding Note : Each images along with qrcode code is render using iframe so what you in web page contain 2 iframe each row to display qrode along with images of a products

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jQuery - How to combine has() and gt()

- by KatieK

With jQuery 1.4.2, I can't figure out how to combine has() with :gt. I'd like to select any ul which contains more than 3 lis, so here's what I've tried: $(document).ready(function(){ $("ul.collapse:has(li:gt(2))") .each( function() { $(this).css("border", "solid red 1px"); }); }); This does work with the 1.2.6 jQuery library, but not 1.3.2 or 1.4.2. I'd appreciate any help in understanding what's going on here. Thanks!

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After pip installing uWSGI there's no /etc/uwsgi/ directory - how can I use apps-enabled?

- by orokusaki

I've been using apt-get install uwsgi to install uWSGI. Today, I realized I needed a feature that's not available until uWSGI 1.1, and Ubuntu 12.04.1 doesn't have anything after 1.0.x, at least according to my apt-get install uwsgi=1.1 attempt. So, I used: pip install http://projects.unbit.it/downloads/uwsgi-lts.tar.gz After doing so, I get a message prescribing the use of /usr/local/bin/uwsgi to launch the program. I'm not a guru when it comes to compiling from source, but my understanding is that when you do so, nothing will be changed in the /etc/ directory. Is this correct? If not, why don't I have a /etc/uwsgi/ directory and, more specifically, a /etc/uwsgi/apps-enabled/ directory? Should I simply create the directories when installing uWSGI from source? I was hesitant to do so, considering there is no mention of this in the docs (I don't want something that accidentally works, etc.).

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Does importing of packages change visibility of classes?

- by Roman

I jsut learned that A class may be declared with the modifier public, in which case that class is visible to all classes everywhere. If a class has no modifier (the default, also known as package-private), it is visible only within its own package. This is a clear statement. But this information interfere with my understanding of importing of packages (which easily can be wrong). I thought that importing a package I make classes from the imported package visible to the importing class. So, how does it work? Are public classes visible to all classes everywhere under condition that the package containing the public class is imported? Or there is not such a condition? What about the package-private classes? They are invisible no mater if the containing package was imported or not? ADDED: It seems to me that I got 2 answers which are marked as good (up-voted) and which contradict eachother.

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Listening to another window resize events in C#

- by Steve

Hi all I am implementing a small application (observer) that needs to "attach" itself to the bottom of another window (observed). The latter is not a window inside the application. At this moment I solved by getting the hWnd of the window and querying periodically in a thread the location of the observed window, moving the observer window accordingly. However this is a very inelegant solution. What I would like to do is to listen to the resize event of the observed window so that the observer will react only when necessary. I assume I should use a hook, and I found plenty of ways of doing it, but my lack of knowledge of the C WinAPI is blocking me in understanding which hook I need to create and how (pinvoke/parameters/etc). I'm pretty sure this is quite trivial, and some of you familiar with C/C++ and WinAPI will have the answer ready at hand ;) Thanks

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What's currently the best way to extend Excel using C#?

- by user169867

I have the professional versions of VS2008 & VS2010. I wish to add a couple buttons to a toolbar in Excel. When they are clicked I'd like to be able to open a form (either WinForms or WPF is fine) collect a few values from the user in the form and then take that data + read cell values from the current worksheet to perform some database operations. What's currently the best way to do this using C#? I'd greatly appreciate a pointer to any examples / tutorials. My understanding is that VS2010 has improved the process alot but I may have to deal w/ Excel 2003 which I don't think it supports. I get confused between Visual Studio 2008s Extensibility-Shared Addin template and other Office Addin templates I've seen. I'm not sure when which type of solution is appropriate. I'm new to Office development so I'd really appreciate any help to get me going on the right track. Thanks much.

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Has anyone been successful at a assembler based led blinker for an xcore?

- by dwelch

I am liking the http://www.xmos.com chips but want to get a lower level understanding of what is going on. Basically assembler. I am trying to sort out something as simple as an led blinker, set the led, count to N clear the led, count to N, loop forever. Sure I can disassemble a 10 line XC program, but if you have tried that you will see there is a lot of bloat in there that is in every program, what bits are to support the compiler output and what bits are actually setting up the gpio?

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Assigning large UInt32 constants in VB.Net

- by Kumba

I inquired on VB's erratic behavior of treating all numerics as signed types back in this question, and from the accepted answer there, was able to get by. Per that answer: Visual Basic Literals Also keep in mind you can add literals to your code in VB.net and explicitly state constants as unsigned. So I tried this: Friend Const POW_1_32 As UInt32 = 4294967296UI And VB.NET throws an Overflow error in the IDE. Pulling out the integer overflow checks doesn't seem to help -- this appears to be a flaw in the IDE itself. This, however, doesn't generate an error: Friend Const POW_1_32 As UInt64 = 4294967296UL So this suggests to me that the IDE isn't properly parsing the code and understanding the difference between Int32 and UInt32. Any suggested workarounds and/or possible clues on when MS will make unsigned data types intrinsic to the framework instead of the hacks they currently are?

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Parsing and validating arbitrary date formats in ruby (on rails)

- by Matt Briggs

I have a requirement to handle custom date formats in an existing app. The idea is that the users have to do with multiple formats from outside sources they have very little control over. We will need to be able to take the format and both validate Dates against it, as well as parse strings specifically in that format. The other thing is that these can be completely arbitrary, like JA == January, FE == February, etc... to my understanding, chronic only handles parsing (and does it in a more magical way then I can use), and enter code here DateTime#strptime comes close, but doesn't really handle the whole two character month scenario, even with custom formatters. The 'nuclear' option is to write in custom support for edge cases like this, but I would prefer to use a library if something like this exists.

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How useful are design patterns when it comes to web programming?

- by Raja

Background: My organization uses Microsoft .Net (3.5) with SQL Server 2005 as back end. With RAD being the norm and Agile being the widely used process. I have always found using design patterns difficult since it involves a bit more understanding and bit more training. Can you give me some examples where design patterns have solved real time problems in Web programming? What is the criteria for using any design pattern? What is the benefit reaped from it. I know it is a general question but this would help me a bunch.

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Moving to OOP hopefully!

- by Luke

So I am trying to understand OOP more and use it. The following code was written before i started using OOP. //loop through all the users $game = "$_POST[Game]_teams"; $result = mysql_query("SELECT username FROM `users`") or die(mysql_error()); while( $row=mysql_fetch_assoc($result) ) { $u[] = $row['username']; } I have put the query into my database page like following: function selectAllUsers() { $q = "SELECT username FROM ".TBL_USERS.""; mysql_query($q, $this->connection); } I'm a little confused about how the rest could be different? Would it be? Is it possible for anyone to help me without more code or understanding of my structure?

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