WebService异步调用与委托有关

1. using System;
2. using System.Collections.Generic;
3. using System.ComponentModel;
4. using System.Data;
5. using System.Drawing;
6. using System.Linq;
7. using System.Text;
8. using System.Windows.Forms;
10. namespace WindowsFormsApplication1
11. {
12.       public partial class Form1 : Form
13.       {
14.           public Form1()
15.           {
16.               InitializeComponent();
17.           }
19.           private void button1_Click(object sender, EventArgs e)
20.           {
21.               localhost.Service t = new WindowsFormsApplication1.localhost.Service();
22.               MessageBox.Show(t.HelloWorld());
23.               MessageBox.Show("Down!");
24.           }
26.           private void button2_Click(object sender, EventArgs e)
27.           {
28.               localhost.Service t = new WindowsFormsApplication1.localhost.Service();
29.               t.HelloWorldCompleted += new WindowsFormsApplication1.localhost.HelloWorldCompletedEventHandler(t_HellowordCompleted);
30.               t.HelloWorldAsync();
31.               MessageBox.Show("Down!");
32.           }
33.           private void t_HellowordCompleted(object sender, localhost.HelloWorldCompletedEventArgs e)
34.           {
35.               MessageBox.Show(e.Result.ToString());
36.           }
38.           private void button3_Click(object sender, EventArgs e)
39.           {
40.               MessageBox.Show((new localhost.Service()).GetTime());
41.           }
42.       }
43. }
44. －－－－－－－－－－－－－－－－－－－－－webService----------------------------
45. using System;
46. using System.Linq;
47. using System.Web;
48. using System.Web.Services;
49. using System.Web.Services.Protocols;
50. using System.Xml.Linq;
51. using System.Threading;
53. [WebService(Namespace = "http://tempuri.org/")]
54. [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
55. // To allow this Web Service to be called from script, using ASP.NET AJAX, uncomment the following line. 
56. // [System.Web.Script.Services.ScriptService]
57. public class Service : System.Web.Services.WebService
58. {
59.      public Service () {
61.          //Uncomment the following line if using designed components 
62.          //InitializeComponent(); 
63.      }
65.      [WebMethod]
66.      public string HelloWorld() {
67.          Thread.Sleep(3000);
68.          return "Hello World";
69.      }
70.     ////缓存10秒
71.      [WebMethod(false,System.EnterpriseServices.Transactionoption.NotSupported,10)]
72.      public string GetTime()
73.      {
74.          return DateTime.Now.ToString();
75.      }
76.     
77. }