Today I ran into a strange problem that made me waste an hour or two, so I thought I’d write about it in case someone else faces the same issue. The SearchBox control was introduced in Windows 8.1 to enable search scenarios from within a Windows Store app. One of its features is that it can show suggestions based on user input. There are three kinds of suggestions: History suggestions are search queries previously entered by the user.

If you’re writing a client application that needs to store user credentials, it’s usually not a good idea to store the password as plain text, for obvious security reasons. So you need to encrypt it, but as soon as you start to think about encryption, it raises all kinds of issues… Which algorithm should you use? Which encryption key? Obviously you will need the key to decrypt the password, so it needs to be either in the executable or in the configuration.

Today I’d like to share a trick I used while developing my first Windows Store application. I’m very new to this technology and it’s my first article about it, so I hope I won’t make a fool of myself… It’s often useful to be notified when the value of a dependency property changes; many controls expose events for that purpose, but it’s not always the case. For instance, recently I was trying to detect when the Content property of a ContentControl changed.

Caller info attributes are one of the new features of C# 5. They’re attributes applied to optional method parameters that enable you to pass caller information implicitly to a method. I’m not sure that description is very clear, so an example will help you understand: static void Log( string message, [CallerMemberName] string memberName = null, [CallerFilePath] string filePath = null, [CallerLineNumber] int lineNumber = 0) { Console.WriteLine( "[{0:g} - {1} - {2} - line {3}] {4}", DateTime.

Visual Studio 2012 RC is out since last week, and even though I didn’t have much time to play with it yet, I think I like it so far. Lots of things have already been said about the design, and about the most important new features, but there are also many smaller and less remarkable improvements that make life easier for us. Since I have seen little or nothing written about those, I thought I would make a list of what I noticed so far.

WPF provides a simple mechanism for shaping collections of data, via the ICollectionView interface and its Filter, SortDescriptions and GroupDescriptions properties: // Collection to which the view is bound public ObservableCollection People { get; private set; } ... // Default view of the People collection ICollectionView view = CollectionViewSource.GetDefaultView(People); // Show only adults view.Filter = o => ((Person)o).Age >= 18; // Sort by last name and first name view.SortDescriptions.Add(new SortDescription("LastName", ListSortDirection.

Today I’d like to share a trick that I used quite often in the past few months. Let’s assume that in order to improve the look of your application, you created custom styles for the standard controls: OK, I’m not a designer… but it will serve the purpose well enough to illustrate my point ;). These styles are very simple, they’re just the default styles of CheckBox and RadioButton in which I only changed the templates to replace the BulletChromes with these awesome blue tick marks.

It’s been a while since I last wrote about markup extensions… The release of Visual Studio 11 Developer Preview, which introduces a number of new features to WPF, just gave me a reason to play with them again. The feature I’m going to discuss here is perhaps not the most impressive, but it fills in a gap of the previous versions: the support of markup extensions for events. Until now, it was possible to use a markup extension in XAML to assign a value to a property, but we couldn’t do the same to subscribe to an event.

Regardless of the programming language you’re using, there are tasks for which the most natural implementation uses a recursive algorithm (even if it’s not always the optimal solution). The trouble with the recursive approach is that it can use a lot of space on the stack: when you reach a certain recursion depth, the memory allocated for the thread stack runs out, and you get a stack overflow error that usually terminates the process (StackOverflowException in .

Note: The code in this article is out of date; the current code is hosted on GitHub. WPF is a great technology, but sometimes it seems to be missing some really basic features… A frequently mentioned example is the lack of support for animated GIF images. Actually, the GIF format itself is supported by the imaging API, but the Image control only shows the first frame of the animation. Many solutions to this problem have been proposed on technical forums and blogs, usually variations of the following approaches: