C#生成JSON数据

        protected void Page_Load(object sender, EventArgs e)
        {
            Response.Clear();
            Response.ContentType = "application/json;charset=utf-8";

            string str = "";
            DataSet ds = SqlHelper.GetSqlDataSet("select top 3 Staff_id,name_sc as Staff_name from [tbl_ac_info] where status='A'");

            List<tbl_ac_info> list = new List<tbl_ac_info>();
            foreach (DataRow item in ds.Tables[].Rows)
            {
                list.Add(new tbl_ac_info() { Staff_id = item[].ToString(), Staff_name = item[].ToString() });
            }
            str = ObjToJSON(list);
            Response.Write(str);
            Response.End();
        }

    [DataContract]
    [Serializable]
    public class tbl_ac_info
    {
        [DataMember]
        public string Staff_id { set; get; }
        [DataMember]
        public string Staff_name { set; get; }

    }

        /// <summary>
        /// 生成JSON字符
        /// </summary>
        /// <param name="obj">待生成的对象,如泛型实体</param>
        /// <returns></returns>
        protected string ObjToJSON(object obj)
        {
            DataContractJsonSerializer serializer = new DataContractJsonSerializer(obj.GetType());
            Stream stream = new MemoryStream();
            serializer.WriteObject(stream, obj);
            stream.Position = ;
            StreamReader streamReader = new StreamReader(stream);
            return streamReader.ReadToEnd();
        }

<script type="text/javascript">
    $(function () {
        GetJSON();
    });
    function GetJSON() {
        $.getJSON("Ajax.aspx?action=export_app&n=" + Math.random(), { "div": "", "app_type": "formula" }, function (data) {
            $("#listStaff_id").html("<font color=green>数据加载中...</font>");
            if (data.length > 0) {
                var list = "";
                $.each(eval(data), function (index, json) {
                    list += json.Staff_id + " / " + json.Staff_name + "<br>";
                });
                $("#listStaff_id").html(list);
            }
            else {
                $("#listStaff_id").html("没有记录");
            }
        });
    }
</script>

须引入命名空间：
using System.Runtime.Serialization.Json;
using System.ServiceModel.Web;