private void BtnDeleteAdministrator_Click(object sender, RoutedEventArgs e)
        {
            if (!Validation())
            {
                return;
            }



            if (MessageBox.Show("Do you want to delete this Administrator?", "Question", MessageBoxButton.YesNo, MessageBoxImage.Information) == MessageBoxResult.Yes)
            {
                dr.DeleteAdministrator(ad.Id);
                ResetTextBox();
                btnAddAdministrator.Visibility    = Visibility.Visible;
                btnUpdateAdministrator.Visibility = Visibility.Hidden;
                btnDeleteAdministrator.Visibility = Visibility.Hidden;
                FillDG();
            }
        }