ASP.NET中调用WebService

在分布式计算中经常要用到WebService，为了更好的学习WebService，写此文供自己记忆。

编译环境:VS2008

在项目中添加一个名称为MyWebService.asmx的Web服务，App_Code文件夹下会新增一个MyWebService.cs文件，编写代码如下:

using System;using System.Collections;using System.Linq;using System.Web;using System.Web.Services;using System.Web.Services.Protocols;using System.Xml.Linq;/// <summary>///MyWebService 的摘要说明/// </summary>[WebService(Namespace = "http://tempuri.org/")][WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]//若要允许使用 ASP.NET AJAX 从脚本中调用此 Web 服务，请取消对下行的注释。 // [System.Web.Script.Services.ScriptService]public class MyWebService : System.Web.Services.WebService {    public MyWebService () {        //如果使用设计的组件，请取消注释以下行         //InitializeComponent();     }    [WebMethod]    public string HelloWorld() {        return "Hello World";    }    }

写好WebService以后，在项目上右键选择“添加Web引用”，可以给WebService起一个命名空间localhost。

添加Web引用成功如下图所示：

下面我们写客户端代码

前端代码:

<form id="form1" runat="server">    <div>        <asp:Button ID="Button1" runat="server" Text="同步调用WebService"  />        <asp:Button ID="Button2" runat="server" Text="异步调用WebService"  />        <asp:Button ID="Button3" runat="server" Text="另一种异步调用WebService"  />    </div></form>

后台代码:

using System;using System.Configuration;using System.Data;using System.Linq;using System.Web;using System.Web.Security;using System.Web.UI;using System.Web.UI.HtmlControls;using System.Web.UI.WebControls;using System.Web.UI.WebControls.WebParts;using System.Xml.Linq;public partial class _Default : System.Web.UI.Page {    protected void Page_Load(object sender, EventArgs e)    {              Button1.Click += new EventHandler(Button1_Click);       Button2.Click += new EventHandler(Button2_Click);       Button3.Click += new EventHandler(Button3_Click);    }    #region 同步调用    void Button1_Click(object sender, EventArgs e)    {        localhost.MyWebService mws = new localhost.MyWebService();        string s = mws.HelloWorld();        Response.Write("<script>alert('"+s+"')</script>");        //Response.End();    }    #endregion    #region 异步调用    void Button2_Click(object sender, EventArgs e)    {        localhost.MyWebService AsyMWS = new localhost.MyWebService();        IAsyncResult asyncResult = AsyMWS.BeginHelloWorld(new AsyncCallback(CallbackFunc), "AsyncState");        string s = AsyMWS.EndHelloWorld(asyncResult);        Response.Write("<script>alert('" + s + "')</script>");    }    void CallbackFunc(IAsyncResult r)    {        Response.Write("<script>alert('异步调用完成!')</script>");    }    #endregion    #region 另一种异步调用    void Button3_Click(object sender, EventArgs e)    {        localhost.MyWebService AsyMWS = new localhost.MyWebService();        AsyMWS.HelloWorldCompleted += new localhost.HelloWorldCompletedEventHandler(AsyMWS_HelloWorldCompleted);        AsyMWS.HelloWorldAsync();    }    void AsyMWS_HelloWorldCompleted(object sender, localhost.HelloWorldCompletedEventArgs e)    {        string s = e.Result;        Response.Write("<script>alert('"+s+"')</script>");    }    #endregion}

注:若要使用最后一种异步调用方式需要在前端代码中写入Async="true"，如下图