private void GetBands()
 {
     try
     {
         FacebookContext context = new FacebookContext();
         context.Load<Band>(context.GetBandsQuery(AccessToken),
             (loadOp) =>
             {
                 if (!loadOp.HasError)
                 {
                     Bands.Clear();
                     foreach (Band band in loadOp.Entities)
                         Bands.Add(band);
                 }
                 else
                     MessageBox.Show(loadOp.Error.ToString());
             },
             null);
     }
     catch (Exception ex)
     {
         MessageBox.Show(ex.ToString());
     }
 }
 private void SetAccessToken(Action callback)
 {
     FacebookContext context = new FacebookContext();
     context.GetAccessToken(App.Current.FacebookSettings.AccessTokenUrl,
         App.Current.FacebookSettings.ApplicationID,
         App.Current.FacebookSettings.RedirectUrl,
         App.Current.FacebookSettings.ApplicationSecret,
         AuthorizationCode,
         (invokeOp) =>
         {
             if (!invokeOp.HasError)
             {
                 AccessToken = invokeOp.Value;
                 if (callback != null)
                     callback();
             }
             else
                 MessageBox.Show(invokeOp.Error.ToString());
         },
         null);
 }