1 namespace main
 2 {
 3     class Program
 4     {
 5         public static string Result = string.Empty;
 6         
 7         static void Main(string[] args)
 8         {
 9           
10             Stopwatch sw = Stopwatch.StartNew();
11 
12             string strIP = "111.13.55.3";//请求的IP地址
13 
14             Console.WriteLine("===== AsyncInvoke 异步回调开始 =====");
15 
16             GetCityIpHandler handler = new GetCityIpHandler(GetIp);
17 
18             ////其核心在于IAsyncResult接口的实现
19             IAsyncResult res = handler.BeginInvoke(strIP, new AsyncCallback(GetIpSyn), string.Format("===== 主线程耗时{0}毫秒! =====", sw.ElapsedMilliseconds));
20 
21             Console.WriteLine("===== 继续执行其他的事情... =====");
22 
23             Console.WriteLine("===== AsyncInvoke 异步回调完毕！=====");
24 
25             sw.Stop();
26 
27             Console.ReadLine();
28 
29         }
30         public delegate string GetCityIpHandler(string strIp);
31         /// <summary>
32         /// 同步方法
33         /// </summary>
34         /// <param name="strIP"></param>
35         /// <returns></returns>
36         public static string GetIp(string strIp)
37         {
38             IpAddressSearchWebServiceSoapClient ws = new IpAddressSearchWebServiceSoapClient();
39             Stopwatch sw = Stopwatch.StartNew();
40             string[] strArea_IP = ws.getCountryCityByIp(strIp);
41             sw.Stop();//这里我们进行漫长的调用
42             return Result = string.Format("IP归属地为{0},查询耗时为{1}毫秒.", strArea_IP[1], sw.ElapsedMilliseconds);
43         }
44         /// <summary>
45         /// 异步回调方法
46         /// </summary>
47         /// <param name="result"></param>
48         static void GetIpSyn(IAsyncResult result)
49         {
50             GetCityIpHandler hl = (GetCityIpHandler)((AsyncResult)result).AsyncDelegate;//AsyncResult 继承自IAsyncResult接口
51             Result = hl.EndInvoke(result);
52             Console.WriteLine(Result); //打印调用GetIp返回的数据
53             object obj = result.AsyncState;
54             Console.WriteLine(obj);//打印返回结果：用户定义的对象，它限定或包含关于异步操作的信息。
55         }
56     }
57 }