public ActionResult AddressAndPayment(FormCollection values)
        {
            var order = new Order();
            TryUpdateModel(order);

            try
            {
                if (string.Equals(values["PromoCode"], PromoCode, StringComparison.OrdinalIgnoreCase) == false)
                {
                    return View(order);
                }
                else
                {
                    order.Username = User.Identity.Name;
                    order.OrderDate = DateTime.Now;

                    storeDB.Orders.Add(order);
                    storeDB.SaveChanges();

                    var cart = ShoppingCart.GetCart(this.HttpContext);
                    cart.CreateOrder(order);

                    return RedirectToAction("Complete", new {id = order.OrderID});

                }
            }
            catch
            {
                return View(order);
            }
        }
        public int CreateOrder(Order order)
        {
            decimal orderTotal = 0;

            var cartItems = GetCartItems();

            foreach (var item in cartItems)
            {
                var orderDetail = new OrderDetail
                {
                    CarID = item.CarID,
                    OrderID = order.OrderID,
                    UnitPrice = item.Car.Price,
                    Quantity = item.Count
                };

                orderTotal += (item.Count*item.Car.Price);

                storeDB.OrderDetails.Add(orderDetail);
            }

            order.Total = orderTotal;

            storeDB.SaveChanges();

            EmptyCart();

            return order.OrderID;
        }