How to use GraphicsCapturePicker in WinUI 3? Error when invoking.

[bitbound]

I'd like to use the GraphicsCapturePicker in a WinUI 3 Desktop app. However, I get the following error when running this code:

    var isSupported = GraphicsCaptureSession.IsSupported(); // true
    var picker = new GraphicsCapturePicker();
    var item = await picker.PickSingleItemAsync();

System.Runtime.InteropServices.COMException: 'The application called an interface that was marshalled for a different thread. (0x8001010E (RPC_E_WRONG_THREAD))'

For WPF, I was able to get around this using the examples here:
https://github.com/Microsoft/Windows.UI.Composition-Win32-Samples/tree/master/dotnet/WPF/ScreenCapture

But the same technique doesn't appear to be working with WinUI. Specifically, marshalling the DispatcherQueueController here returns null: https://github.com/microsoft/Windows.UI.Composition-Win32-Samples/blob/master/dotnet/WPF/ScreenCapture/Composition.WindowsRuntimeHelpers/CoreMessagingHelper.cs

What do I need to do to get the GraphicsCapturePicker to work?

Thanks! :)

[bitbound]

Nevermind. I figured it out! :) Here's the interop calls that need to be made:

            var hwnd = WindowNative.GetWindowHandle(_mainWindow);
            var picker = new GraphicsCapturePicker();
            InitializeWithWindow.Initialize(picker, hwnd);
            var item = await picker.PickSingleItemAsync();

[OxOld]

nice

[codedocu]

great... thank you

[Fygadi]

Thx a lot u helped me too!