public IActionResult Cart()
        {
            CMyViewModel viewModel = new CMyViewModel()
            {
                ProductName        = "Apple",
                ProductDescription = "xxxxx",
                ProductQuantity    = 123
            };

            return(View(viewModel));
        }
        public IActionResult Cart(CMyViewModel viewmodel)
        {
            RemoveDisplayingDataValidation();
            if (ModelState.IsValid)
            {
                return(RedirectToAction("Cart"));
            }

            CMyViewModel viewModel = new CMyViewModel()
            {
                ProductName     = "Pear",
                ProductQuantity = 100
            };

            return(View(viewModel));
        }