easyui Accordion 动态数据源问题

[yfchenjun]

静态时这种格式
var _menus = { menus:
[{ menuname: "设备管理" , icon: "icon-blank" , menus:
[{ menuname: "设备管理", icon: "icon-itemblue", url: "Device/Info/List.aspx" },
{ menuname: "设备控制", icon: "icon-itemblue", url: "Device/Control/List.aspx" },
{ menuname: "设备分组管理", icon: "icon-itemblue", url: "Device/Group/List.aspx"}]
},

{ menuname: "发布管理", icon: "icon-blank", menus:
[{ menuname: "频道", icon: "icon-itemblue", url:"Publish/Channel/List.aspx"},
{ menuname: "播放列表", icon: "icon-itemblue", url: "Publish/Programme/List.aspx" },
},

{ menuname: "接口管理", icon: "icon-blank", menus: []}]
};
现在我要重数据库获取数据
通过jquery ajax调用服务器的一个方法；
var _menus= getjsondata(传入一个用户编号);

请大侠帮我完善一下服务器端的方法

        public string GetUserPowerInfo(long id)
        {
            DataTable dt = null;
            StringBuilder jsonBuilder = new StringBuilder();

            if (dt.Rows.Count > 0)
            {
                for (int i = 0; i < dt.Rows.Count; i++)
                {
                    jsonBuilder.Append("{");
                    jsonBuilder.Append("\"menus\":[");
                    jsonBuilder.Append("\"");
                    jsonBuilder.Append("\"menuname\":");
                    jsonBuilder.Append("菜单名称");
                    jsonBuilder.Append("\",\"icon\":");
                    jsonBuilder.Append("图标");
                    jsonBuilder.Append("\",\"menus\":[");
                    foreach (string col in dt.Rows)
                    {
                        jsonBuilder.Append("\"");
                        jsonBuilder.Append(dt.Rows[i][col].ToString());
                        jsonBuilder.Append("\",");
                    }
                    jsonBuilder.Append("\"]\"");
                    jsonBuilder.Append("]},");
                }
                jsonBuilder.Remove(jsonBuilder.Length - 1, 1);
            }

            return jsonBuilder.ToString();

        }