[WCF]Web客户端调用WCF服务后,回调返回结果不显示,请大家帮帮忙

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="WebApplication1._Default" %>



<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">



<html xmlns="http://www.w3.org/1999/xhtml" >

<head runat="server">

    <title></title>

</head>

<body>

    <form id="form1" runat="server">

    <asp:ScriptManager ID="ScriptManager1" runat="server">

    </asp:ScriptManager>

    <div>

        <asp:UpdatePanel ID="UpdatePanel1" runat="server">

        <ContentTemplate>

        <asp:TextBox ID="TextBox1" runat="server" Height="345px" TextMode="MultiLine"></asp:TextBox>

        <asp:Button ID="Button1" runat="server" onclick="Button1_Click" Text="Button" />

        <asp:Button ID="Button2" runat="server" onclick="Button2_Click" Text="Button" />

        <asp:Button ID="Button3" runat="server" onclick="Button3_Click" Text="Button" />

        <asp:Button ID="Button4" runat="server" onclick="Button4_Click" Text="Button" />

        </ContentTemplate>

        </asp:UpdatePanel>

    </div>

    

    </form>

</body>

</html>

using System;

using System.Collections.Generic;

using System.Web;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.ServiceModel;



namespace WebApplication1

{

    public partial class _Default : System.Web.UI.Page,WebClientTest.ICalculatorDuplexCallback

    {

        //WebClientTest为引用的WCF服务命名空间

        WebClientTest.CalculatorDuplexClient client;

        double value;

        protected void Page_Load(object sender, EventArgs e)

        {

            InstanceContext instanceContext = new InstanceContext(this);

            //每次执行Button事件,client都为空.

            // Create a client

            if (client == null)

            {

                //创建WCF服务的客户端

                client = new WebClientTest.CalculatorDuplexClient(instanceContext);

            }          

        }



        #region ICalculatorDuplexCallback 成员

        /// <summary>

        /// 实现回调成员

        /// </summary>

        /// <param name="result1"></param>

        public void Result(double result1)

        {

            this.TextBox1.Text += result1.ToString() + "\r\n";

            

        }



        public void Equation(string eqn)

        {

            this.TextBox1.Text += eqn + "\r\n";

        }



        #endregion



        protected void Button1_Click(object sender, EventArgs e)

        {

            // Call the AddTo service operation.

            //调用WCF服务

            value = 100.00D;

            client.AddTo(value);

        }



        protected void Button2_Click(object sender, EventArgs e)

        {

            // Call the SubtractFrom service operation.

            value = 50.00D;

            client.SubtractFrom(value);

        }



        protected void Button3_Click(object sender, EventArgs e)

        {

            // Call the MultiplyBy service operation.

            value = 17.65D;

            client.MultiplyBy(value);

        }



        protected void Button4_Click(object sender, EventArgs e)

        {

            // Call the DivideBy service operation.

            value = 2.00D;

            client.DivideBy(value);

        }

    }

}