How can i override back button as I used to?

Question

I've just installed Windows Phone 8.1 SDK, and had an application in mind. But I cant even navigate back and forth! Back button the phone exit the application by default, and since all the pages now inherits "Page" the override for the back button isnt exposed.

Read http://msdn.microsoft.com/en-us/library/windows/apps/xaml/dn639128.aspx but I don't understand it, how can I implement it?

Answer 1

Take a look at any of the WP Projects that are included with Visual Studio (eg: The Hub App project). Or add a new "BasicPage" to your application. You will notice that they are using a NAvigationHelper to subscribe to the BackPressed event for you already. The post you linked to explains it pretty well.

The most important thing to know about the BackPressed event that is raised when the user presses the back button is that if your app does not handle the event, by setting BackPressedEventArgs.Handled property to true, the operating system will suspend your app and return the user to the previous experience

The example is given in that post

private void HardwareButtons_BackPressed(object sender, BackPressedEventArgs e)
{
    Frame frame = Window.Current.Content as Frame;
    if (frame == null)
    {
       return;
    }

    if (frame.CanGoBack)
    {
        frame.GoBack();
        e.Handled = true;
   }

}

Notice it sets e.Handled = true; to indicate that the app should not "close". You are saying "Hey, I've got this handled already". In the example, it will navigate to the previous page.