public static Response CheckOut(List <DetailedCart> Cart, string paymentId, int userId) { if (paymentId == "" || paymentId.All(char.IsDigit) != true) { return(new Response(false, "Payment ID cannot be empty or non numeric")); } int _paymentId = Int32.Parse(paymentId); if (PaymentTypeHandler.GetPaymentType(_paymentId) == null) { return(new Response(false, "Wrong Payment Type ID")); } if (Cart == null) { return(new Response(false, "Cart Cannot be empty")); } TransactionHandler.CheckOut(Cart, _paymentId, userId); return(new Response(true, "Cart successfully checked out")); }