title: WP8 Applicationbar hidding on rotation change
body: <p>I have this kind of code in my app to hide the SystemTray, and i cant do this same for the Applicationbar. Why? I want to change the isVisible property on rotation change.</p>
  
  <p>This is the code:</p>
  
  <pre><code>private void PhoneApplicationPage_BeginLayoutChanged(object sender, OrientationChangedEventArgs e)
      {
          if (e.Orientation == PageOrientation.PortraitUp)
          {
              AppBar.IsVisible = true;
              SystemTray.IsVisible = true;
          }
          else
          {
              AppBar.IsVisible = false;
              SystemTray.IsVisible = false;
          }
      }
  </code></pre>
  
  <p>I named the applicationbar to AppBar but i cant change this property, i tried to look whats wrong and on debugging i see the value for AppBar is null, why?</p>
  
  <p>Is there any other method so i can hide it on roation change?! Am i doing something wrong? Because this method wroks for hiding the SystemTray</p>