将对象保存在cookise中

  /// <summary>
    /// 存储历史记录到cookise中
    /// </summary>
    /// <param name="history"></param>
    /// <returns></returns>
    public static bool SaveHistoryCookies(List<HistoryEntity> history)
    {
        try
        {

            BinaryFormatter bf = new BinaryFormatter();  //声明一个序列化类

            MemoryStream ms = new MemoryStream();  //声明一个内存流

            bf.Serialize(ms, history);  //执行序列化操作

            byte[] result = new byte[ms.Length];

            result = ms.ToArray();

            string temp = System.Convert.ToBase64String(result);

            /*此处为关键步骤，将得到的字节数组按照一定的编码格式转换为字符串，不然当对象包含中文时，进行反序列化操作时会产生编码错误*/

            ms.Flush();

            ms.Close();

            HttpCookie cookie = new HttpCookie("history");  //声明一个Key为person的Cookie对象

            cookie.Expires = DateTime.Now.AddDays(30.0);  //设置Cookie的有效期,此处时间可以根据需要设置

            cookie.Value = temp;  //将cookie的Value值设置为temp
            System.Web.HttpContext.Current.Response.Cookies.Add(cookie);

            return true;
        }
        catch (Exception ex)
        {
            return false;
        }
    }

 /// <summary>
    /// 读取历史记录
    /// </summary>
    /// <returns></returns>
    public static List<HistoryEntity> ReadHistoryCookies()
    {
        try
        {
            string result = System.Web.HttpContext.Current.Request.Cookies["history"].Value;

            byte[] b = System.Convert.FromBase64String(result);  //将得到的字符串根据相同的编码格式分成字节数组

            MemoryStream ms = new MemoryStream(b, 0, b.Length);  //从字节数组中得到内存流

            BinaryFormatter bf = new BinaryFormatter();

            return bf.Deserialize(ms) as List<HistoryEntity>;  //反序列化得到history类对象
        }
        catch (Exception)
        {

            return null;
        }


    }