private void CancelButton_Click(object sender, RoutedEventArgs e)
 {
     OnCanceling();
     if (_dialogResult == true)
     {
         if (ProductModelDataForm != null)
         {
             RaiseCanExecuteChanged();
             NavStateTrue();
             ProductModelDataForm.CancelEdit();
             ProductModelDataForm.BeginEdit();
         }
     }
 }