private void Root_PointerPressed(object sender, PointerRoutedEventArgs e)
 {
     if (e.Pointer.PointerDeviceType == Windows.Devices.Input.PointerDeviceType.Touch)
     {
         // Tell the system to use the gestures from this pointer point (if it can).
         _interactionSource.Capture(e.GetCurrentPoint(Root));
     }
 }