Game.IsActive Property

public bool IsActive { get; }

Property Value

On Windows, a game is active if it is not minimized and has the current input focus.

On Xbox 360, the game is active if the user is not interacting with the Guide or Dashboard.

On Windows Phone, the game is active if it is the current application interacting with the user, not obscured by any Guide dialogs and the phone screen is not locked.

Best Practice
It is generally a good idea to pause the game when Game.IsActive is false.

Reference