测试结果

NET4.5 实现代码

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Script.Serialization;
using System.Web.Services;

namespace Webservice
{
    /// <summary>
    /// WebService1 的摘要说明
    /// </summary>
    [WebService(Namespace = "http://tempuri.org/")]
    [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
    [System.ComponentModel.ToolboxItem(false)]
    // 若要允许使用 ASP.NET AJAX 从脚本中调用此 Web 服务，请取消注释以下行。 
    // [System.Web.Script.Services.ScriptService]
    public class WebService1 : System.Web.Services.WebService
    {

        class User
        {
            public string UserName;
            public string UserPhone;
        }

        [WebMethod]
        public void JSONdemo()
        {
            User user = new User();
            user.UserName = "json";
            user.UserPhone = "12345678";

            JavaScriptSerializer serializer = new JavaScriptSerializer();
            var json = serializer.Serialize(user);

            //主要是下面的两句 
            Context.Response.Write(json);
            Context.Response.End();

        }

    }
}