title: WP7 Stop page from Navigating/Going back
body: <p>How do I stop my application from going back when the user clicks on the "Cancel" button after hitting the back button?</p>
  
  <pre><code>      protected override void OnBackKeyPress(System.ComponentModel.CancelEventArgs e)
      {
          var buttonInfo = MessageBox.Show("Are you sure you want to exit?", "Exit", MessageBoxButton.OKCancel);
          if (buttonInfo == MessageBoxResult.OK)
          {
              this.NavigationService.GoBack();
          }
          else
          {
              //How to stop page from navigating
          }
      }
  </code></pre>