public IActionResult OnGet(string message) { var serializer = new JavaScriptSerializer(); var value = Request.Cookies[CookieName]; var cartItems = _productQuery.CheckIsInStock(serializer.Deserialize <List <CartItem> >(value)); if (cartItems.Any(i => !i.IsInStock)) { return(RedirectToPage("Cart")); } foreach (var item in cartItems) { item.CalculateTotalPrice(); } Cart = _calculateCart.ComputeCart(User.Identity.Name, cartItems); _cartService.SetCart(Cart); Message = message; return(Page()); }