购物车序列化

　　网上找到的一个购物车类，但是经过反复的测试，发现其中序列化后数据会出现问题，改成以下的模块就正常了。

 /// <summary>
        /// 将ShoppingCart写入Cookie
        /// </summary>
        /// <param name="SC">ShoppingCart对象</param>
        /// <param name="CookieName">CookieName，默认为ShoppingCart</param>
        public static string ShopCartToCookie(ShoppingCart SC, string CookieName)
        {
            if (CookieName == null || CookieName=="") { CookieName = "ShoppingCart"; }
            if (SC == null)
            {
                WriteCookie(CookieName, "",148);
                return "";
            }
            else
            {
                IFormatter fm = new BinaryFormatter();
                MemoryStream sm = new MemoryStream();
                fm.Serialize(sm, SC);
                byte[] bty = new byte[sm.Length];
                bty = sm.ToArray();
                string strCart = Convert.ToBase64String(bty);
                strCart = System.Web.HttpContext.Current.Server.UrlEncode(strCart);
                WriteCookie(CookieName, strCart,148);
                return strCart;
            }
        }


        /// <summary>
        /// 将Cookie反序列化为ShopCart
        /// </summary>
        /// <param name="CookieName">CookieName，默认为ShopCart</param>
        public static ShoppingCart CookieToShopCart(string CookieName)
        {
            if (CookieName == null || CookieName=="") { CookieName = "ShoppingCart"; }
            string StrCart = System.Web.HttpContext.Current.Server.UrlDecode(GetCookie(CookieName));
           
            if (StrCart==null||StrCart=="")
            {
                return null;
            }
            byte[] bt = Convert.FromBase64String(StrCart);
            Stream sm = new MemoryStream(bt);
            IFormatter fm = new BinaryFormatter();
            ShoppingCart SC = (ShoppingCart)fm.Deserialize(sm);
            if (SC==null)
            {
                return null;
            }
            else
            {
                return SC;
            }
        }