public void RefreshDeviceBookmarks()
 {
     if (IsPageEnabled)
     {
         List <Bookmark> serviceBookmarks = null;
         BackgroundHelper.Execute(() =>
         {
             serviceBookmarks = BookmarkService.RetrieveDeviceBookmarks();
             BackgroundHelper.ExecuteUIThread(() =>
             {
                 DeviceBookmarks.Clear();
                 foreach (Bookmark bookmark in serviceBookmarks)
                 {
                     DeviceBookmarks.Add(new ItemViewModel()
                     {
                         Title = bookmark.Title, Url = bookmark.Url
                     });
                 }
             });
         });
     }
 }