private void btnEdit_Click(object sender, RoutedEventArgs e)
        {
            LoyaltyCardModel loyalty = dgvLoyaltyCard.SelectedItem as LoyaltyCardModel;

            if (loyalty != null)
            {
                LoyalCardDetails lcd = new LoyalCardDetails(this, loyalty);
                lcd.ShowDialog();
            }
            else
            {
                System.Windows.MessageBox.Show("No record selected!");
            }
        }
        private void btnAdd_Click(object sender, RoutedEventArgs e)
        {
            LoyalCardDetails lcd = new LoyalCardDetails(this);

            lcd.ShowDialog();
        }