なつねこメモ

[ComImport]
[Guid("3628E81B-3CAC-4C60-B7F4-23CE0E0C3356")]
[InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
public interface IGraphicsCaptureItemInterop
{
    IntPtr CreateForWindow([In] IntPtr hWnd, ref Guid iid);

    IntPtr CreateForMonitor([In] IntPtr hMonitor, ref Guid iid);
}

// hWnd から GraphicsCaptureItem を作ってあげる
public static class UwpInterop
{
    public static GraphicsCaptureItem CreateItemForWindow(IntPtr hWnd)
    {
        var factory = WindowsRuntimeMarshal.GetActivationFactory(typeof(GraphicsCaptureItem));
        var interop = (IGraphicsCaptureItemInterop) factory;
        var iid = typeof(GraphicsCaptureItem).GetInterface("IGraphicsCaptureItem").GUID;
        var pointer = interop.CreateForWindow(hWnd, ref iid);
        var capture = Marshal.GetObjectForIUnknown(pointer) as GraphicsCaptureItem;
        Marshal.Release(pointer);

        return capture;
    }
}