非同步委托的簡單用例

 1 //定義一個委托
 2 static Func<int, int, string> delFunc = (a, b) =>
 3 {
 4     Console.WriteLine("委托線程：" + Thread.CurrentThread.ManagedThreadId);
 5     return (a + b).ToString();
 6 };
 7 
 8 static void Main(string[] args)
 9 {
10     Console.WriteLine("主線程：" + Thread.CurrentThread.ManagedThreadId);
11 
12     //同步調用委托
13     //string str = delFunc(3,4);//str = delFunc.Invoke(3, 4);
14 
15     //非同步調用委托(原理：用線程池中線程，執行委托指向的方法)
16     IAsyncResult ar = delFunc.BeginInvoke(3, 4, CallBackFn, "我是回調函數參數");//回調函數和回調函數參數
17     //string result = delFunc.EndInvoke(ar);//EndInvoke方法會阻塞，等待非同步委托的結束
18 
19     Console.ReadLine();
20 }
21 
22 //非同步委托執行完成後，回調的函數
23 static void CallBackFn(IAsyncResult iar)
24 {
25     object obj = iar.AsyncState;//我是回調函數參數
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);//非同步委托的結果，在這裡委托已經執行完畢，不會再阻塞。
30 
31     Console.WriteLine("回調線程：" + Thread.CurrentThread.ManagedThreadId);
32 }