線程、任務和同步學習筆記（一）

1、創建線程的一種簡單方法是定義一個委托，並非同步調用它。

 1 using System;
 2 using System.Threading;
 3 
 4 delegate int WaitAWhileDelegate(int data, int ms);
 5 
 6 class Program
 7 {
 8     static void Main(string[] args)
 9     {
10         WaitAWhileDelegate d = WaitAWhile;
11         int data = 1;
12         int ms = 3000;
13         IAsyncResult a = d.BeginInvoke(data, ms, null, null);
14         while (!a.IsCompleted)
15         {
16             Console.Write("*");
17             Thread.Sleep(100);
18         }
19         int result = d.EndInvoke(a);
20         Console.WriteLine("\nresult: {0}", result);
21     }
22 
23     static int WaitAWhile(int data, int ms)
24     {
25         Console.WriteLine("WaitAWhile started.");
26         Thread.Sleep(ms);
27         Console.WriteLine("WaitAWhile completed.");
28         return ++data;
29     }
30 }

增加代碼中第17行的Sleep方法的參數值，輸出的星號的個數會減少，反之會增加。

運行結果：

 2、IAsyncResult有一個名字叫AsyncWaitHandle的屬性，該屬性的類型是WaitHandle類。該類的WaitOne方法會“將一個超時時間作為可選的第一個參數，在其中可以定義要等待的最長時間”。

 1 using System;
 2 using System.Threading;
 3 
 4 class Program
 5 {
 6     delegate int WaitAWhileDelegate(int data, int ms);
 7 
 8     static void Main(string[] args)
 9     {
10         WaitAWhileDelegate d = new WaitAWhileDelegate(WaitAWhile);
11         int data = 1;
12         int ms = 3000;
13         IAsyncResult a = d.BeginInvoke(data, ms, null, null);
14         while (true)
15         {
16             Console.Write("*");
17             if (a.AsyncWaitHandle.WaitOne(50, false))
18             {
19                 Console.WriteLine("Can get the result now.");
20                 break;
21             }
22         }
23         int result = d.EndInvoke(a);
24         Console.WriteLine("\nresult: {0}", result);
25     }
26 
27     static int WaitAWhile(int data, int ms)
28     {
29         Console.WriteLine("WaitAWhile started.");
30         Thread.Sleep(ms);
31         Console.WriteLine("WaitAWhile completed.");
32         return ++data;
33     }
34 }

運行結果：