void OnLoaded(object sender, RoutedEventArgs e)
 {
     Model = new StockDataViewModel(grid);
     Model.Resume();
     Application.Current.DebugSettings.EnableFrameRateCounter = false;
     grid.CustomSummary += grid_CustomSummary;
 }
 void OnUnloaded(object sender, RoutedEventArgs e)
 {
     grid.CustomSummary -= grid_CustomSummary;
     Model.Unload();
     Model = null;
 }