void XnaWindowHost_Loaded(object sender, RoutedEventArgs e)
 {
     // If we don't yet have a GraphicsDeviceService reference, we must add one for this control
     if (graphicsService == null)
     {
         graphicsService = GraphicsDeviceService.AddRef(hWnd, (int)ActualWidth, (int)ActualHeight);
         services.AddService<IGraphicsDeviceService>(graphicsService);
         // Invoke the LoadContent event
         if (LoadContent != null)
             LoadContent(this, new GraphicsDeviceEventArgs(graphicsService.GraphicsDevice));
     }
 }
        protected override void Dispose(bool disposing)
        {
            // Release our reference to the GraphicsDeviceService if we have one
            if (graphicsService != null)
            {
                graphicsService.Release(disposing);
                graphicsService = null;
            }

            // Unhook the Rendering event so we no longer attempt to draw
            CompositionTarget.Rendering -= CompositionTarget_Rendering;

            base.Dispose(disposing);
        }