运行状态处理

当转到运行状态时，有与此事件相关的特殊处理程序：打开“App.xaml.cx”类并查看 OnLaunched 方法 - 当用户从已终止状态打开应用程序时，此方法被激活：

protected override void OnLaunched(LaunchActivatedEventArgs e)
    {
        Frame 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();

            rootFrame.NavigationFailed += OnNavigationFailed;

           //You can get information about previous state of the app:

            if (e.PreviousExecutionState == ApplicationExecutionState.Terminated)
            {
                //The app was previously suspended but was then shutdown 
                //at some point because the system needed to reclaim memory.
            }
            if (e.PreviousExecutionState == ApplicationExecutionState.ClosedByUser)
            {
                //The user closed the app with the close gesture in tablet mode,
                //or with Alt+F4.When the user closes the app, it is first suspended
                //and then terminated.
            }
            if (e.PreviousExecutionState == ApplicationExecutionState.NotRunning)
            {
                //An app could be in this state because it hasn't been launched since the last time
                //the user rebooted or logged in. It can also be in this state if it was running 
                //but then crashed, or because the user closed it earlier.
            }
            if (e.PreviousExecutionState == ApplicationExecutionState.Running)
            {
                //The app was already open when the user tried to launch it again
            }
            if (e.PreviousExecutionState == ApplicationExecutionState.Suspended)
            {
                //The user either minimized or switched away from your app
                //and didn't return to it within a few seconds.
            }

            // Place the frame in the current Window
            Window.Current.Content = rootFrame;
        }

        //When available system resources allow, the startup performance of Windows Store
        //apps on desktop device family devices is improved by proactively launching
        //the user’s most frequently used apps in the background. A prelaunched app 
        //is put into the suspended state shortly after it is launched.Then, when the
        //user invokes the app, the app is resumed by bringing it from the suspended
        //state to the running state--which is faster than launching the app cold.
        //The user's experience is that the app simply launched very quickly.
        if (e.PrelaunchActivated == false)
        {
            if (rootFrame.Content == null)
            {
                rootFrame.Navigate(typeof(MainPage), e.Arguments);
            }
            Window.Current.Activate();
        }
    }