/// <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>
private 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();
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);
FlyoutService = new FlyoutService();
FlyoutService.FlyoutResolver = CreateFlyoutView;
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();
}
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);
}
/// <summary>
/// Invoked when this page will no longer be displayed in a Frame.
/// </summary>
/// <param name="e">Event data that describes how this page was reached. The Parameter
/// property provides the group to be displayed.</param>
protected override void OnNavigatedFrom(NavigationEventArgs e)
{
var frameFacade = new FrameFacadeAdapter(this.Frame);
var frameState = GetSessionStateForFrame(frameFacade);
var pageState = new Dictionary <String, Object>();
this.SaveState(pageState);
frameState[_pageKey] = pageState;
}
/// <summary>
/// Invoked when this page is about to be displayed in a Frame.
/// </summary>
/// <param name="e">Event data that describes how this page was reached. The Parameter
/// property provides the group to be displayed.</param>
protected override void OnNavigatedTo(NavigationEventArgs e)
{
if (e == null)
{
throw new ArgumentNullException("e");
}
// Returning to a cached page through navigation shouldn't trigger state loading
if (this._pageKey != null)
{
return;
}
var frameFacade = new FrameFacadeAdapter(this.Frame);
var frameState = GetSessionStateForFrame(frameFacade);
this._pageKey = "Page-" + frameFacade.BackStackDepth;
if (e.NavigationMode == NavigationMode.New)
{
// Clear existing state for forward navigation when adding a new page to the
// navigation stack
var nextPageKey = this._pageKey;
int nextPageIndex = frameFacade.BackStackDepth;
while (frameState.Remove(nextPageKey))
{
nextPageIndex++;
nextPageKey = "Page-" + nextPageIndex;
}
// Pass the navigation parameter to the new page
this.LoadState(e.Parameter, null);
}
else
{
// Pass the navigation parameter and preserved page state to the page, using
// the same strategy for loading suspended state and recreating pages discarded
// from cache
this.LoadState(e.Parameter, (Dictionary <String, Object>)frameState[this._pageKey]);
}
}
/// <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>
private 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();
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);
FlyoutService = new FlyoutService();
FlyoutService.FlyoutResolver = CreateFlyoutView;
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();
}
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;
}
/// <summary>
/// Invoked when this page is about to be displayed in a Frame.
/// </summary>
/// <param name="e">Event data that describes how this page was reached. The Parameter
/// property provides the group to be displayed.</param>
protected override void OnNavigatedTo(NavigationEventArgs e)
{
if (e == null) throw new ArgumentNullException("e");
// Returning to a cached page through navigation shouldn't trigger state loading
if (this._pageKey != null) return;
var frameFacade = new FrameFacadeAdapter(this.Frame);
var frameState = GetSessionStateForFrame(frameFacade);
this._pageKey = "Page-" + frameFacade.BackStackDepth;
if (e.NavigationMode == NavigationMode.New)
{
// Clear existing state for forward navigation when adding a new page to the
// navigation stack
var nextPageKey = this._pageKey;
int nextPageIndex = frameFacade.BackStackDepth;
while (frameState.Remove(nextPageKey))
{
nextPageIndex++;
nextPageKey = "Page-" + nextPageIndex;
}
// Pass the navigation parameter to the new page
this.LoadState(e.Parameter, null);
}
else
{
// Pass the navigation parameter and preserved page state to the page, using
// the same strategy for loading suspended state and recreating pages discarded
// from cache
this.LoadState(e.Parameter, (Dictionary<String, Object>)frameState[this._pageKey]);
}
}
/// <summary>
/// Invoked when this page will no longer be displayed in a Frame.
/// </summary>
/// <param name="e">Event data that describes how this page was reached. The Parameter
/// property provides the group to be displayed.</param>
protected override void OnNavigatedFrom(NavigationEventArgs e)
{
var frameFacade = new FrameFacadeAdapter(this.Frame);
var frameState = GetSessionStateForFrame(frameFacade);
var pageState = new Dictionary<String, Object>();
this.SaveState(pageState);
frameState[_pageKey] = pageState;
}
