AdventureWorks.WebServices.Controllers.ShoppingCartController.AddProductToShoppingCart C# (CSharp) Method

        public void AddProductToShoppingCart(string id, string productIdToIncrement)
        {
            lock (_lock)
            {
                var product = _productRepository.GetProducts().FirstOrDefault(c => c.ProductNumber == productIdToIncrement);
                if (product == null)
                {
                    throw new HttpResponseException(HttpStatusCode.NotFound);
                }

                _shoppingCartRepository.AddProductToCart(id, product);
            }
        }