如果在 wpf c# 中使用 thread.join() 如何避免服务器繁忙窗口

Question

I have a c++ application and use clr to call the below c# method . Everything is going good except for one thing. As wpf window needs STA thread , I'm trying to create a new thread with STA state and start it. This makes the wpf window modeless , even if the window is started with show dialog . So I tried using thread.join() to make the caller thread to wait until the thread completes or window closes. using thread.join() shows server busy window after a few seconds. (I'm not doing any operation related to the internet in my application).

How to make the caller thread to wait until the window closes? or How to get rid of Server busy window?

        void ShowWindow()
        {
            _ownerHandle = Process.GetCurrentProcess().MainWindowHandle;
            Thread newWindowThread = new Thread(new ThreadStart(() =>
            {
                MyWpfWindow window = new MyWpfWindow();
                MyWpfWindowViewModel vm = new MyWpfWindowViewModel();

                WindowInteropHelper helper = new WindowInteropHelper(window);
                helper.Owner = _ownerHandle;

                window.DataContext = vm;

                window.ShowDialog();

            }));

            // set the apartment state  this will only invoke the WPF window  
            newWindowThread.SetApartmentState(ApartmentState.STA);
            newWindowThread.IsBackground = true;
            // start the thread  
            newWindowThread.Start();
            //waits this thread here untill the newWindowThread execution completes.
            newWindowThread.Join();

        }

Also, I tried with a while loop as below to block the current main thread.

while(!windowShown)
{
}

in the place of newWindowThread.join(). After using this, my window is not visible.

I'm getting a server busy window as below

Answer 1

Calling Join() blocks the current thread. If you want to wait asynchronously, you could use a SemaphoreSlim :

static async Task ShowWindowAsync()
{
    SemaphoreSlim semaphore = new SemaphoreSlim(0, 1);
    _ownerHandle = Process.GetCurrentProcess().MainWindowHandle;
    Thread newWindowThread = new Thread(new ThreadStart(() =>
    {
        MyWpfWindow window = new MyWpfWindow();
        MyWpfWindowViewModel vm = new MyWpfWindowViewModel();
        WindowInteropHelper helper = new WindowInteropHelper(window);
        helper.Owner = _ownerHandle;
        window.DataContext = vm;
        window.Closed += (s, e) =>
        {
            semaphore.Release();
            semaphore.Dispose();
        };
        window.ShowDialog();

    }));

    // set the apartment state  this will only invoke the WPF window  
    newWindowThread.SetApartmentState(ApartmentState.STA);
    newWindowThread.IsBackground = true;
    // start the thread  
    newWindowThread.Start();
    //waits this thread here untill the newWindowThread execution completes.
    await semaphore.WaitAsync();
}