What happend when I lock my screen and unlock go back to my application?

I fou开发者_运维技巧nd when I lock my phone screen and unlock,The xaml page seems to be reload.This is not the point,the point is the whole program I wrote is just like fresh restart.It is true?What can I do with this issue?

You should read the Execution Model Overview. Your app is getting Tombstoned. You need to handle this.

An application in the foreground can continue to run when the phone screen is locked by setting the PhoneApplicationService.ApplicationIdleDetectionMode property. By setting up your application to run when the phone screen is locked, a user is able to access the application quickly upon unlock. However, when your application runs under a locked screen, it could consume power outside of the user's control. For this reason, your application must minimize power usage when running under a locked screen