/// <summary>Creates the application's root frame and loads the first page if needed.
/// Also calls <see cref="OnInitializedAsync"/> when the application is instantiated the first time. </summary>
/// <param name="executionState">The application execution state. </param>
/// <returns>The task. </returns>
protected async Task InitializeFrameAsync(ApplicationExecutionState executionState)
{
if (Window.Current.Content == null)
{
WindowContent = CreateWindowContentElement();
RootFrame = GetFrame(WindowContent);
MtSuspensionManager.RegisterFrame(RootFrame, "AppFrame");
if (executionState == ApplicationExecutionState.Terminated)
{
await RestoreStateAsync();
}
var task = OnInitializedAsync(RootFrame, executionState);
if (task != null)
{
await task;
}
Window.Current.Content = WindowContent;
}
else
{
RootFrame = GetFrame(Window.Current.Content);
}
if (RootFrame.Content == null)
{
RootFrame.Initialize(StartPageType);
}
Window.Current.Activate();
}