/// <summary>
/// Invoked when application execution is being suspended. Application state is saved
/// without knowing whether the application will be terminated or resumed with the contents
/// of memory still intact.
/// </summary>
/// <param name="sender">The source of the suspend request.</param>
/// <param name="e">Details about the suspend request.</param>
private async void OnSuspending(object sender, SuspendingEventArgs e)
{
IsSuspending = true;
try
{
var deferral = e.SuspendingOperation.GetDeferral();
//Bootstrap inform navigation service that app is suspending.
NavigationService.Suspending();
// Save application state
await SessionStateService.SaveAsync();
deferral.Complete();
}
finally
{
IsSuspending = false;
}
}
/// <summary>
/// Initializes the Frame and its content.
/// </summary>
/// <param name="args">The <see cref="IActivatedEventArgs"/> instance containing the event data.</param>
/// <returns>A task of a Frame that holds the app content.</returns>
protected async Task <Frame> InitializeFrameAsync(IActivatedEventArgs args)
{
var rootFrame = Window.Current.Content as Frame;
// Do not repeat app initialization when the Window already has content,
// just ensure that the window is active
if (rootFrame == null)
{
// Create a Frame to act as the navigation context and navigate to the first page
rootFrame = new Frame();
if (ExtendedSplashScreenFactory != null)
{
Page extendedSplashScreen = this.ExtendedSplashScreenFactory.Invoke(args.SplashScreen);
rootFrame.Content = extendedSplashScreen;
}
var frameFacade = new FrameFacadeAdapter(rootFrame);
//Initialize MvvmAppBase common services
SessionStateService = new SessionStateService();
//Configure VisualStateAwarePage with the ability to get the session state for its frame
VisualStateAwarePage.GetSessionStateForFrame =
frame => SessionStateService.GetSessionStateForFrame(frameFacade);
//Associate the frame with a key
SessionStateService.RegisterFrame(frameFacade, "AppFrame");
NavigationService = CreateNavigationService(frameFacade, SessionStateService);
SettingsPane.GetForCurrentView().CommandsRequested += OnCommandsRequested;
// Set a factory for the ViewModelLocator to use the default resolution mechanism to construct view models
ViewModelLocator.SetDefaultViewModelFactory(Resolve);
OnRegisterKnownTypesForSerialization();
if (args.PreviousExecutionState == ApplicationExecutionState.Terminated)
{
await SessionStateService.RestoreSessionStateAsync();
}
OnInitialize(args);
if (args.PreviousExecutionState == ApplicationExecutionState.Terminated)
{
// Restore the saved session state and navigate to the last page visited
try
{
SessionStateService.RestoreFrameState();
NavigationService.RestoreSavedNavigation();
_isRestoringFromTermination = true;
}
catch (SessionStateServiceException)
{
// Something went wrong restoring state.
// Assume there is no state and continue
}
}
// Place the frame in the current Window
Window.Current.Content = rootFrame;
}
return(rootFrame);
}