1 /// <summary>
2 /// Designates a Windows Presentation Foundation application model with added functionalities.
3 /// </summary>
4 public class UIHelper : Application
5 {
6 private static DispatcherOperationCallback exitFrameCallback = new DispatcherOperationCallback(ExitFrame);
7
8 /// <summary>
9 /// Processes all UI messages currently in the message queue.
10 /// </summary>
11 public static void DoEvents()
12 {
13 // Create new nested message pump.
14 DispatcherFrame nestedFrame = new DispatcherFrame();
15
16 // Dispatch a callback to the current message queue, when getting called,
17 // this callback will end the nested message loop.
18 // note that the priority of this callback should be lower than the that of UI event messages.
19 DispatcherOperation exitOperation = Dispatcher.CurrentDispatcher.BeginInvoke(
20 DispatcherPriority.Background, exitFrameCallback, nestedFrame);
21
22 // pump the nested message loop, the nested message loop will
23 // immediately process the messages left inside the message queue.
24 Dispatcher.PushFrame(nestedFrame);
25
26 // If the "exitFrame" callback doesn't get finished, Abort it.
27 if (exitOperation.Status != DispatcherOperationStatus.Completed)
28 {
29 exitOperation.Abort();
30 }
31 }
32
33 private static Object ExitFrame(Object state)
34 {
35 DispatcherFrame frame = state as DispatcherFrame;
36 // Exit the nested message loop.
37 if (frame != null)
38 {
39 frame.Continue = false;
40 }
41 return null;
42 }
43
44 }
