Hi,

I have an attached behavior defined thusly,..

    public static class FileBrowserBehaviour
{


	public static bool GetBrowsesOnClick(DependencyObject obj)
	{
		return (bool)obj.GetValue(BrowsesOnClickProperty);
	}

	public static void SetBrowsesOnClick(DependencyObject obj, bool value)
	{
		obj.SetValue(BrowsesOnClickProperty, value);
	}

	// Using a DependencyProperty as the backing store for BrowsesOnClick.  This enables animation, styling, binding, etc...
	public static readonly DependencyProperty BrowsesOnClickProperty =
		DependencyProperty.RegisterAttached("BrowsesOnClick", typeof(bool), typeof(FileBrowserBehaviour), new FrameworkPropertyMetadata(false, new PropertyChangedCallback(BrowsesOnClickChanged)));


	public static void BrowsesOnClickChanged(DependencyObject obj, DependencyPropertyChangedEventArgs args)
	{
		FrameworkElement fe = obj as FrameworkElement;

		if ((bool)args.NewValue)
		{
			fe.PreviewMouseLeftButtonDown += new MouseButtonEventHandler(OpenFileBrowser);
		}
		else
		{
			fe.PreviewMouseLeftButtonDown -= new MouseButtonEventHandler(OpenFileBrowser);
		}
	}

	static void OpenFileBrowser(object sender, MouseButtonEventArgs e)
	{
		var tb = sender as TextBox;
		if (tb.Text.Length < 1 || tb.Text=="Click to browse..")
		{
			OpenFileDialog ofd = new OpenFileDialog();
				ofd.Filter = "Executables | *.exe";
				if (ofd.ShowDialog() == true)
				{
					Debug.WriteLine("Setting textbox text-" + ofd.FileName);
					tb.Text = ofd.FileName;
					Debug.WriteLine("Set textbox text");
				}
		}
	}
}

It's a nice simple attached behavior which pops open an OpenFileDialog when you click on a textbox and puts the filename in the box when you're done.

It works maybe 40% of the time but the rest of the time the whole app hangs. The call stack at this point looks like this -

[Managed to Native Transition]

WindowsBase.dll!MS.Win32.UnsafeNativeMethods.GetMessageW(ref System.Windows.Interop.MSG msg, System.Runtime.InteropServices.HandleRef hWnd, int uMsgFilterMin, int uMsgFilterMax) + 0x15 bytes WindowsBase.dll!System.Windows.Threading.Dispatcher.GetMessage(ref System.Windows.Interop.MSG msg, System.IntPtr hwnd, int minMessage, int maxMessage) + 0x48 bytes WindowsBase.dll!System.Windows.Threading.Dispatcher.PushFrameImpl(System.Windows.Threading.DispatcherFrame frame = {System.Windows.Threading.DispatcherFrame}) + 0x8b bytes WindowsBase.dll!System.Windows.Threading.Dispatcher.PushFrame(System.Windows.Threading.DispatcherFrame frame) + 0x49 bytes WindowsBase.dll!System.Windows.Threading.Dispatcher.Run() + 0x4c bytes PresentationFramework.dll!System.Windows.Application.RunDispatcher(object ignore) + 0x1e bytes PresentationFramework.dll!System.Windows.Application.RunInternal(System.Windows.Window window) + 0x6f bytes PresentationFramework.dll!System.Windows.Application.Run(System.Windows.Window window) + 0x26 bytes PresentationFramework.dll!System.Windows.Application.Run() + 0x19 bytes Debugatron.exe!Debugatron.App.Main() + 0x5e bytes C# [Native to Managed Transition] [Managed to Native Transition] mscorlib.dll!System.AppDomain.nExecuteAssembly(System.Reflection.Assembly assembly, string[] args) + 0x19 bytes mscorlib.dll!System.Runtime.Hosting.ManifestRunner.Run(bool checkAptModel) + 0x6e bytes mscorlib.dll!System.Runtime.Hosting.ManifestRunner.ExecuteAsAssembly() + 0x84 bytes mscorlib.dll!System.Runtime.Hosting.ApplicationActivator.CreateInstance(System.ActivationContext activationContext, string[] activationCustomData) + 0x65 bytes mscorlib.dll!System.Runtime.Hosting.ApplicationActivator.CreateInstance(System.ActivationContext activationContext) + 0xa bytes mscorlib.dll!System.Activator.CreateInstance(System.ActivationContext activationContext) + 0x3e bytes Microsoft.VisualStudio.HostingProcess.Utilities.dll!Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssemblyDebugInZone() + 0x23 bytes mscorlib.dll!System.Threading.ThreadHelper.ThreadStart_Context(object state) + 0x66 bytes mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state) + 0x6f bytes mscorlib.dll!System.Threading.ThreadHelper.ThreadStart() + 0x44 bytes

Now, I've seen this kind of thing before when doing some asynchronous stuff but there's none of that going on at that point. The only thread alive is the UI thread! Also, I always get that last debug statement when it does hang.

Can anyone point me in the right direction? This one's driving me crazy!