C#之线程和线程池（Thread和ThreadPool类）

注：要使用此方法都需要引入应用：using System.Threading;//引入应用

参数意义：将要执行的方法排入队列以便执行，WaitCallback，即表示将要执行的方法；Object，包含方法所用数据的对象。如果将方法成功排入队列，则为 true；否则为 false。

一、下面是ThreadPool.QueueUserWorkItem 方法 (WaitCallback)的示例代码：

 1 using System;
 2 using System.Collections.Generic;
 3 using System.Linq;
 4 using System.Text;
 5 using System.Threading;//引入应用
 6
 7 namespace QueueUserWorkItem_WaitCallback_
 8 {
 9     class Program
10     {
11         static void Main(string[] args)
12         {
13             // Queue the task.
14             ThreadPool.QueueUserWorkItem(new WaitCallback(ThreadProc));
15
16             Console.WriteLine("Main thread does some work, then sleeps.");
17             // If you comment out the Sleep, the main thread exits before
18             // the thread pool task runs.  The thread pool uses background
19             // threads, which do not keep the application running.  (This
20             // is a simple example of a race condition.)
21             Thread.Sleep(1000);
22
23             Console.WriteLine("Main thread exits.");
24         }
25
26         // This thread procedure performs the task.
27         static void ThreadProc(Object stateInfo)
28         {
29             // No state object was passed to QueueUserWorkItem, so
30             // stateInfo is null.
31             Console.WriteLine("Hello from the thread pool.");
32         }
33     }
34 }

运行以上代码后：

二、下面是ThreadPool.QueueUserWorkItem 方法 (WaitCallback, Object)的示例代码：

 1 using System;
 2 using System.Collections.Generic;
 3 using System.Linq;
 4 using System.Text;
 5 using System.Threading;
 6
 7 namespace QueueUserWorkItem__WaitCallback__Object_
 8 {
 9     //将方法排入队列以便执行，并指定包含该方法所用数据的对象。 此方法在有线程池线程变得可用时执行。
10     /*
11      *
12      * public static bool QueueUserWorkItem(WaitCallback callBack,Object state)
13      *
14      *
15      * callBack  类型：System.Threading.WaitCallback
16      * WaitCallback ，它表示要执行的方法。
17      *
18      *
19      * state     类型：System.Object
20      * 包含方法所用数据的对象。
21      *
22      *
23      * 返回值    类型：System.Boolean
24      * 如果此方法成功排队，则为 true；如果无法将该工作项排队，则引发 NotSupportedException。
25      *
26      *
27      * 注：如果回调方法需要复杂数据，可以定义包含这些数据的类。
28      *
29      */
30     class Program
31     {
32         static void Main(string[] args)
33         {
34             // Create an object containing the information needed for the task.
35             TaskInfo ti = new TaskInfo("This report displays the number {0}.", 42);
36
37             // Queue the task and data.
38             ThreadPool.QueueUserWorkItem(new WaitCallback(ThreadProc), ti);
39
40             Console.WriteLine("Main thread does some work, then sleeps.");
41
42             // If you comment out the Sleep, the main thread exits before
43             // the ThreadPool task has a chance to run.  ThreadPool uses
44             // background threads, which do not keep the application
45             // running.  (This is a simple example of a race condition.)
46             Thread.Sleep(1000);
47
48             Console.WriteLine("Main thread exits.");
49         }
50
51         // The thread procedure performs the independent task, in this case
52         // formatting and printing a very simple report.
53         //
54         static void ThreadProc(Object stateInfo)
55         {
56             TaskInfo ti = (TaskInfo)stateInfo;
57             Console.WriteLine(ti.Boilerplate, ti.Value);
58         }
59     }
60
61     // TaskInfo holds state information for a task that will be
62     // executed by a ThreadPool thread.
63     public class TaskInfo
64     {
65         // State information for the task.  These members
66         // can be implemented as read-only properties, read/write
67         // properties with validation, and so on, as required.
68         public string Boilerplate;
69         public int Value;
70
71         // Public constructor provides an easy way to supply all
72         // the information needed for the task.
73         public TaskInfo(string text, int number)
74         {
75             Boilerplate = text;
76             Value = number;
77         }
78     }
79 }

运行以上代码后：