WebService方法代码：
[WebMethod]
public string HelloWorld() {
System.Threading.Thread.Sleep(3000);
return "Hello World";
}
调用wsdl ****.asmx /o:d:"ServiceA.cs
生成WebService代理类，并加入工程
调用页代码：
public partial class _Default : System.Web.UI.Page
{
global::_ServiceA serviceA = new _ServiceA();
protected void Page_Load(object sender, EventArgs e)
{
}
protected void Button1_Click(object sender, EventArgs e) {
this.TextBox1.Text = "";
AsyncCallback asyncCallback = new AsyncCallback(CallBackExec);
IAsyncResult asyncResult = serviceA.BeginHelloWorld(asyncCallback, null);
asyncResult.AsyncWaitHandle.WaitOne();
/*
也可不用回调函数asyncCallBack
string result = "";
if (asyncResult.IsCompleted) {
result = serviceA.EndHelloWorld(asyncResult);
}
this.TextBox1.Text = result;*/
}
private void CallBackExec(IAsyncResult asyncResult) {
Response.Write("CallBackExec() called!");
Response.Write(asyncResult.IsCompleted);
this.TextBox1.Text = serviceA.EndHelloWorld(asyncResult);
}
}