Every Windows Phone project contains App.cs class:
public sealed partial class App : Application
This class is your global application context.
General Application class usage:
- App entry point, particularly for various activation contracts.
- Application lifecycle management.
- Application global resources/services initialization.
- Unhandled exception detection.
Application Life Cycle Events
In App.cs you can subscribe to life cycle events: Suspending, Resuming
Raised when your application state changed to Suspending state. Suspending state means that your app isn't visible by the user (occurs when user switches to another app), it's the only indication that you get before your app is terminated. That's why this is where you'll want to save your session state, such as movie position that currently played, or some other valuable state information).
Raised while when your application is back from Suspending mode. The OS restores the app state automatically (your page that you've been on when application Suspended), this is where you should restore your application state that could be changed by the time your app was suspended.
Application virtual methods
Also you have two virtual methods that you can override:
protected virtual void OnActivated(IActivatedEventArgs args); protected virtual void OnLaunched(LaunchActivatedEventArgs args);
Called when the application is activated somehow (not normal launching). You won't get here if you simply launch the app by clicking a tile. For example, you'll get here when another app launches your app. (You can the IActivatedEventArgs.Kind for activation reason).
Invoked when the application is launched. This method will be called every time your application launched. Generally used as main point for application initialization.