public static string InsertWishlist(string product_id)
        {
            string result     = "";
            string customerID = "";

            if (HttpContext.Current.Request.Cookies["CustomerID"] != null)
            {
                customerID = HttpContext.Current.Request.Cookies["CustomerID"].Value;
                if (customerID.Length <= 0)
                {
                    result = "Fail";
                }
                else
                {
                    WishlistController obj_wishlist_control = new WishlistController();
                    Wishlist           obj_wishlist         = new Wishlist();
                    obj_wishlist.ProductID  = product_id;
                    obj_wishlist.CustomerID = customerID;
                    obj_wishlist.AddedDate  = DateTime.Now;
                    result = obj_wishlist_control.InsertWishlist(obj_wishlist);
                }
            }
            else
            {
                result = "Fail";
            }

            return(result);
        }