Using the WPF Dispatcher in unit tests

By using the Visual Studio Unit Test Framework you don’t need to initialize the Dispatcher yourself. You are absolutely right, that the Dispatcher doesn’t automatically process its queue.

You can write a simple helper method “DispatcherUtil.DoEvents()” which tells the Dispatcher to process its queue.

C# Code:

public static class DispatcherUtil
{
    [SecurityPermissionAttribute(SecurityAction.Demand, Flags = SecurityPermissionFlag.UnmanagedCode)]
    public static void DoEvents()
    {
        DispatcherFrame frame = new DispatcherFrame();
        Dispatcher.CurrentDispatcher.BeginInvoke(DispatcherPriority.Background,
            new DispatcherOperationCallback(ExitFrame), frame);
        Dispatcher.PushFrame(frame);
    }

    private static object ExitFrame(object frame)
    {
        ((DispatcherFrame)frame).Continue = false;
        return null;
    }
}

You find this class too in the WPF Application Framework (WAF).