public IActionResult Add(Guid id) { ProductViewModel toAdd = _productsService.GetProduct(id); List <ProductViewModel> products = ParseSessionStringToList(); ProductViewModel toCheck = products.FirstOrDefault(x => x.Id == toAdd.Id); if (toCheck != null) { toCheck.Quantity++; TempData["feedback"] = ("Product was added again successfully"); } else { products.Add(toAdd); TempData["feedback"] = ("Product was added successfully"); } //decrease the stock _productsService.DecreaseStock(id); HttpContext.Session.SetString(SessionKeyName, ParseSessionListToString(products)); RefreshInfo(); return(RedirectToAction("Index")); }