public ViewResult UseExtention() { // create and populate Shoppingcart ShoppingCart cart = new ShoppingCart { Products = new List<Product> { new Product {Name = "Kayak",Price = 275M }, new Product {Name = "Lifejacket",Price = 48.95M }, new Product {Name = "Soccer ball",Price = 19.5M }, new Product {Name = "Corner flag",Price = 34.95M } } }; decimal cartTotal = cart.Totalprices(); return View("Result", (object)String.Format("Total: {0:c}", cartTotal)); }