怎样在ASP.NET(C#) 使用Json序列化反序列化问题？

using System;
using System.Collections.Generic;
using System.Web;
using System.Web.Script.Serialization;
using System.Data;
namespace Utils
{
    /// <summary>
    /// JSON帮助类
    /// </summary>
    public class JsonHelper
    {
        /// <summary>
        /// 对象转JSON
        /// </summary>
        /// <param name="obj">对象</param>
        /// <returns>JSON格式的字符串</returns>
        public static string ObjectToJSON(object obj)
        {
            JavaScriptSerializer jss = new JavaScriptSerializer();
            try
            {
                return jss.Serialize(obj);
            }
            catch (Exception ex)
            {
                throw new Exception("JSONHelper.ObjectToJSON(): " + ex.Message);
            }
        }
        /// <summary>
        /// 数据表转键值对集合
        /// 把DataTable转成 List集合, 存每一行
        /// 集合中放的是键值对字典,存每一列
        /// </summary>
        /// <param name="dt">数据表</param>
        /// <returns>哈希表数组</returns>
        public static List<Dictionary<string, object>> DataTableToList(DataTable dt)
        {
            List<Dictionary<string, object>> list
                 = new List<Dictionary<string, object>>();
            foreach (DataRow dr in dt.Rows)
            {
                Dictionary<string, object> dic = new Dictionary<string, object>();
                foreach (DataColumn dc in dt.Columns)
                {
                    dic.Add(dc.ColumnName, dr[dc.ColumnName]);
                }
                list.Add(dic);
            }
            return list;
        }
        /// <summary>
        /// 数据集转键值对数组字典
        /// </summary>
        /// <param name="dataSet">数据集</param>
        /// <returns>键值对数组字典</returns>
        public static Dictionary<string, List<Dictionary<string, object>>> DataSetToDic(DataSet ds)
        {
            Dictionary<string, List<Dictionary<string, object>>> result = new Dictionary<string, List<Dictionary<string, object>>>();
            foreach (DataTable dt in ds.Tables)
                result.Add(dt.TableName, DataTableToList(dt));
            return result;
        }
        /// <summary>
        /// 数据表转JSON
        /// </summary>
        /// <param name="dataTable">数据表</param>
        /// <returns>JSON字符串</returns>
        public static string DataTableToJSON(DataTable dt)
        {
            return ObjectToJSON(DataTableToList(dt));
        }
        /// <summary>
        /// JSON文本转对象,泛型方法
        /// </summary>
        /// <typeparam name="T">类型</typeparam>
        /// <param name="jsonText">JSON文本</param>
        /// <returns>指定类型的对象</returns>
        public static T JSONToObject<T>(string jsonText)
        {
            JavaScriptSerializer jss = new JavaScriptSerializer();
            try
            {
                return jss.Deserialize<T>(jsonText);
            }
            catch (Exception ex)
            {
                throw new Exception("JSONHelper.JSONToObject(): " + ex.Message);
            }
        }
        /// <summary>
        /// 将JSON文本转换为数据表数据
        /// </summary>
        /// <param name="jsonText">JSON文本</param>
        /// <returns>数据表字典</returns>
        public static Dictionary<string, List<Dictionary<string, object>>> TablesDataFromJSON(string jsonText)
        {
            return JSONToObject<Dictionary<string, List<Dictionary<string, object>>>>(jsonText);
        }
        /// <summary>
        /// 将JSON文本转换成数据行
        /// </summary>
        /// <param name="jsonText">JSON文本</param>
        /// <returns>数据行的字典</returns>
        public static Dictionary<string, object> DataRowFromJSON(string jsonText)
        {
            return JSONToObject<Dictionary<string, object>>(jsonText);
        }
    }
}