public ActionResult SearchResults(FormCollection data)
        {
            var laptops = LaptopBLL.Search(data["search"].ToString());
            var phones  = PhoneBLL.Search(data["search"].ToString());
            var tablets = TabletBLL.Search(data["search"].ToString());

            if (laptops.Count == 0 && phones.Count == 0 & tablets.Count == 0)
            {
                ViewBag.Message = "Không tìm thấy sản phẩm nào";
            }
            var products = new ProductViewModels();

            products.Laptops = laptops;
            products.Phones  = phones;
            products.Tablets = tablets;
            return(View(products));
        }