Windows Phone 7: Scrollbar Position after Thombstoning

If you want to give your users the privilege that they are at the same scroll position in a listbox at a Windows Phone 7 application after thombstoning you can use the following code snipplet (usage of the page state):

   1: protected override void OnNavigatedFrom(System.Windows.Navigation.NavigationEventArgs e)

   2:     {

   3:       base.OnNavigatedFrom(e);

   4:  

   5:       // Remember scroll offset

   6:       try

   7:       {

   8:         ScrollViewer viewer = ((VisualTreeHelper.GetChild(listBox, 0) as FrameworkElement).FindName("ScrollViewer") as ScrollViewer);

   9:         State["scrollOffset"] = viewer.VerticalOffset;

  10:       }

  11:       catch { }

  12:     }

  13:  

  14:     protected override void OnNavigatedTo(System.Windows.Navigation.NavigationEventArgs e)

  15:     {

  16:       base.OnNavigatedTo(e);

  17:       object offset;

  18:  

  19:       // Return scroll offset

  20:       if (State.TryGetValue("scrollOffset", out offset))

  21:         listBox.Loaded += delegate

  22:         {

  23:           try

  24:           {

  25:             ScrollViewer viewer = ((VisualTreeHelper.GetChild(listBox, 0) as FrameworkElement).FindName("ScrollViewer") as ScrollViewer);

  26:             viewer.ScrollToVerticalOffset((double)offset);

  27:           }

  28:           catch { }

  29:         };

  30:     }