private void LoyaltyCardNavButton_Click(object sender, RoutedEventArgs e)
        {
            //Load and display the Loyalty Offers page, closing this one.
            LoyaltyCardItemList loyaltyCard = new LoyaltyCardItemList();

            loyaltyCard.Show();
            this.Close();
        }
        private void BackButton_Click(object sender, RoutedEventArgs e)
        {
            //Return to the previous page, closing this one.
            LoyaltyCardItemList loyaltyOffers = new LoyaltyCardItemList();

            loyaltyOffers.Show();
            this.Close();
        }