public static bool add(int productid, int qty) { int userid = Convert.ToInt32(HttpContext.Current.Session["auth_user"]); List <Cart> carts = CartHandler.getCartsById(userid); bool exist = false, exceed = false; if (carts.Count != 0) { foreach (Cart product in carts) { if (product.ProductID == productid) { int newqty = qty + product.Quantity; Product Product = ProductHandler.getProductByID(productid); if (newqty > Product.Stock) { exceed = true; } else { Cart cart = getCart(productid, userid); CartHandler.update(cart, newqty); } exist = true; break; } } } if (!exist || carts.Count == 0) { CartHandler.Add(userid, productid, qty); } if (exceed) { return(false); } else { return(true); } }