protected void btnAddToCart_Click(object sender, EventArgs e)
        {
            //make sure that there are enough units in stock
            if (vldQuantity.IsValid) //<stretch>Should also have server side validation in case of multiple users/connections</stretch>
            {
                NorwinDBTableAdapters.CartTableAdapter     cart     = new NorwinDBTableAdapters.CartTableAdapter();
                NorwinDBTableAdapters.ProductsTableAdapter products = new NorwinDBTableAdapters.ProductsTableAdapter();

                //get input
                int numberToOrder = int.Parse(cbxQuantity.SelectedValue);

                float unitPrice = (float)products.GetUnitPriceByProdID(Convert.ToInt32(Request.QueryString[0]));

                float subTotal = (float)numberToOrder * unitPrice;

                //add the selected quantity of the item to the cart table in the DB
                cart.InsertCartItem(prodName, numberToOrder, prodID, custID, Session.SessionID, unitPrice, subTotal);
                products.UpdateInStock((short)(unitsInStock - numberToOrder), prodID);

                lsvProdDetails.DataSource = products.GetDataByProdID(Convert.ToInt32(Request.QueryString[0]));
                lsvProdDetails.DataBind();

                lblItemAdded.Text = numberToOrder + " items added to order.";
            }
            else
            {
                lblItemAdded.Text = "...";
            }
        }