webservice写的json格式客户端无法读出

json

网上看到很多解答，但我没搞定。
下面是我写的带代码
封装函数

public DataSet js()
 {
 string sql = "select * from friend";
 SqlCommand cmd = new SqlCommand(sql, con);
 //SqlDataReader da = cmd.ExecuteReader();
 SqlDataAdapter da = new SqlDataAdapter(cmd);
 DataSet ds = new DataSet();
 da.Fill(ds);
 cmd.Dispose();
 return ds;
 }

转化数据

public string js()
 {
 StringBuilder sb = new StringBuilder();
    DataTable dt = dbOperation.js().Tables[0];
    sb.Append("{User:[");
    for (int i = 0; i < dt.Rows.Count; i++)
    {
        sb.Append("{\"userid\":\"" + dt.Rows[i]["userid"].ToString() + "\",\"name\":\"" + dt.Rows[i]["name"].ToString() + "\",\"password\":\"" + dt.Rows[i]["password"].ToString() + "\",\"text\":\"" + dt.Rows[i]["text"].ToString() + "\"}");
        if (i != dt.Rows.Count - 1)
        {
            sb.Append(",");
        }
    }
    sb.Append("]}");
    return sb.ToString();

}

运行效果

<?xml version="1.0" encoding="UTF-8"?>
{User:[{"userid":"123456","name":"吉旺","password":"123456 ","text":"asd"},{"userid":"41238","name":"华小坑","password":"123456 ","text":""}]}

客户端读取

var Service=function() {
 Service.initializeBase(this);
 this._timeout = 0;
 this._userContext = null;
 this._succeeded = null;
 this._failed = null;
 }
 Service.prototype={
 _get_path:function() {
 var p = this.get_path();
 if (p) return p;
 else return Service._staticInstance.get_path();},
 HelloWorld:function(succeededCallback, failedCallback, userContext) {
 return this._invoke(this._get_path(), 'HelloWorld',false,{},succeededCallback,failedCallback,userContext); },
 selectAllUser:function(succeededCallback, failedCallback, userContext) {
 return this._invoke(this._get_path(), 'selectAllUser',false,{},succeededCallback,failedCallback,userContext); },
 insertUser:function(name,pwd,succeededCallback, failedCallback, userContext)

麻烦帮助一下