private async void StartProjecting_Click(object sender, RoutedEventArgs e) { // If projection is already in progress, then it could be shown on the monitor again // Otherwise, we need to create a new view to show the presentation if (rootPage.ProjectionViewPageControl == null) { // First, create a new, blank view var thisDispatcher = Window.Current.Dispatcher; await CoreApplication.CreateNewView().Dispatcher.RunAsync(CoreDispatcherPriority.Normal, () => { // ViewLifetimeControl is a wrapper to make sure the view is closed only // when the app is done with it rootPage.ProjectionViewPageControl = ViewLifetimeControl.CreateForCurrentView(); // Assemble some data necessary for the new page var initData = new ProjectionViewPageInitializationData(); initData.MainDispatcher = thisDispatcher; initData.ProjectionViewPageControl = rootPage.ProjectionViewPageControl; initData.MainViewId = thisViewId; // Display the page in the view. Note that the view will not become visible // until "StartProjectingAsync" is called var rootFrame = new Frame(); rootFrame.Navigate(typeof(ProjectionViewPage), initData); Window.Current.Content = rootFrame; }); } try { // Start/StopViewInUse are used to signal that the app is interacting with the // view, so it shouldn't be closed yet, even if the user loses access to it rootPage.ProjectionViewPageControl.StartViewInUse(); // Show the view on a second display (if available) or on the primary display await ProjectionManager.StartProjectingAsync(rootPage.ProjectionViewPageControl.Id, thisViewId); rootPage.ProjectionViewPageControl.StopViewInUse(); } catch (InvalidOperationException) { rootPage.NotifyUser("The projection view is being disposed", NotifyType.ErrorMessage); } }