public JsonResult AddItemToCart(int id, string mySessionID)
        {
            if(mySessionID != null)
            {
                var myCart = ShoppingCartManager.getInstance().getMyShoppingCart(mySessionID);

                if(myCart == null)
                {
                    myCart = new ShoppingCart();
                    myCart.Items = new List<Item>();
                    ShoppingCartManager.getInstance().addShoppingCartToList(myCart);
                }
                var newItem = new ItemBLL().GetById(id);
                if (newItem.InStock > 0) {

                    myCart.Items.Add(newItem);
                    myCart.SessionID = mySessionID;
                    ShoppingCartManager.getInstance().updateCartTotalPrice(myCart);

                    return this.Json(myCart);
                }

            }
            return null;
        }
        public JsonResult GetMyUpdatedCartJSON()
        {
            var mySessionID = Session["SessionID"] as string;

            var myCart = ShoppingCartManager.getInstance().getMyShoppingCart(mySessionID);

            if (myCart == null)
            {
                myCart = new ShoppingCart();
                myCart.Items = new List<Item>();
            }
            myCart.SessionID = mySessionID;
            ShoppingCartManager.getInstance().updateCartTotalPrice(myCart);

            return this.Json(myCart);
        }
 public void updateCartTotalPrice(ShoppingCart cart)
 {
     cart.PriceOfCart = cart.Items.Select(x => x.Price).Sum();
 }
 public void addShoppingCartToList(ShoppingCart newCart)
 {
     shoppingCarts.Add(newCart);
 }