WPF 获取 UI 线程，或如何从非 UI 线程显示窗口

Question

I realized a WPF Control Library to use as an Addin in MS Office 2007.

The WPF-Class is instantiated by the host and creates a toolbar with some buttons in MS Office. By clicking a button the WPF window should appear. The problem is that I always receive the following error: " The calling thread must be STA, because many UI components require this. " My main function is marked as [STAThread].

It seems that the button_Click event runs in an other thread than the UI thread.

I tried to use a dispatcher, but that didn't work.

Dispatcher.CurrentDispatcher.Invoke(
               System.Windows.Threading.DispatcherPriority.Normal,
               new Action(
                 delegate()
                 {
    wpfform wf = new wpfform();
    wf.ShowDialog();
     ));

I think the module gets a wrong dispatcher, but I don't know exactly. Next I tried to start the window in an separate STA thread and join the thread, but this didn't work either. As I removed the [STAThread] Attribute from the main function the window started, but i was unable to access office (because i'm in a separate thread).

Thread workerThread = new Thread(_ShowDialog);
workerThread.SetApartmentState(ApartmentState.STA);
workerThread.Start();
workerThread.Join();

Is it possible to determine the UI thread and create a dispatcher for this thread, or how can I come back to the UI thread?

Answer 1

You will need to use the application UI dispatcher. Try using:

Application.Current.Dispatcher.Invoke(...)

Answer 2

您可以使用 SynchronizationContext，在 stackoverflow 中对此进行了描述：使用 SynchronizationContext 将事件发送回 WinForms 或 WPF 的 UI （您必须在 UI 线程上“捕获”上下文，遗憾的是，该问题的结果是：您应该使用Application.Current.Dispatcher也许你应该看看为什么是空的）