public ActionResult Create(Product product)
        {
            if (ModelState.IsValid)
            {
                db.Products.Add(product);
                db.SaveChanges();
                return RedirectToAction("Index");
            }

            ViewBag.CategoryId = new SelectList(db.Categories, "CategoryId", "CategoryName", product.CategoryId);
            return View(product);
        }
        public void AddToCart(Product product)
        {
            var cartItem = db.Carts.SingleOrDefault(
                c => c.CartId == ShoppingCartId
                && c.ProductId == product.ProductId);

            if (cartItem == null)
            {
                cartItem = new Cart
                {
                    ProductId = product.ProductId,
                    CartId = ShoppingCartId,
                    Count = 1,
                    DateCreated = DateTime.Now
                };
                db.Carts.Add(cartItem);
            }
            else
            {
                cartItem.Count++;
            }

            db.SaveChanges();
        }
 public ActionResult Edit(Product product)
 {
     if (ModelState.IsValid)
     {
         db.Entry(product).State = EntityState.Modified;
         db.SaveChanges();
         return RedirectToAction("Index");
     }
     ViewBag.CategoryId = new SelectList(db.Categories, "CategoryId", "CategoryName", product.CategoryId);
     return View(product);
 }