异步委托的简单用例

 1 //定义一个委托
 2 static Func<int, int, string> delFunc = (a, b) =>
 3 {
 4     Console.WriteLine("委托线程：" + Thread.CurrentThread.ManagedThreadId);
 5     return (a + b).ToString();
 6 };
 7
 8 static void Main(string[] args)
 9 {
10     Console.WriteLine("主线程："+Thread.CurrentThread.ManagedThreadId);
11
12     //同步调用委托
13     //string str = delFunc(3,4);
14
15     //异步调用委托(原理：用线程池中线程，执行委托指向的方法)
16     IAsyncResult ar = delFunc.BeginInvoke(3, 4, CallBackFn, "我是回调函数参数");//回调函数和回调函数参数
17     //string result = delFunc.EndInvoke(ar);//EndInvoke方法会阻塞，等待异步委托的结束
18
19     Console.ReadLine();
20 }
21
22 //异步委托执行完成后，回调的函数
23 static void CallBackFn(IAsyncResult iar)
24 {
25     object obj = iar.AsyncState;//我是回调函数参数
26
27     AsyncResult ar = iar as AsyncResult;
28     Func<int, int, string> del = ar.AsyncDelegate as Func<int, int, string>;
29     string result = del.EndInvoke(ar);//异步委托的结果，在这里委托已经执行完毕，不会再阻塞。
30
31     Console.WriteLine("回调线程：" + Thread.CurrentThread.ManagedThreadId);
32 }