// Code to execute when the application is closing (eg, user hit Back)
 // This code will not execute when the application is deactivated
 private void Application_Closing(object sender, ClosingEventArgs e)
 {
     ExerciseManager.Save(Exercises);
 }
 // Code to execute when the application is deactivated (sent to background)
 // This code will not execute when the application is closing
 private void Application_Deactivated(object sender, DeactivatedEventArgs e)
 {
     ExerciseManager.Save(Exercises);
 }