实例1：直接看看微软提供的代码

using System;using System.Threading;public class Example{    public static void Main()    {        // Queue the task.        ThreadPool.QueueUserWorkItem(new WaitCallback(ThreadProc));        Console.WriteLine("Main thread does some work, then sleeps.");        // If you comment out the Sleep, the main thread exits before        // the thread pool task runs.  The thread pool uses background        // threads, which do not keep the application running.  (This        // is a simple example of a race condition.)        Thread.Sleep(1000);        Console.WriteLine("Main thread exits.");    }    // This thread procedure performs the task.    static void ThreadProc(Object stateInfo)    {        // No state object was passed to QueueUserWorkItem, so         // stateInfo is null.        Console.WriteLine("Hello from the thread pool.");    }}

 

using System;using System.Collections.Generic;using System.Text;using System.Threading;namespace Example{    class ThreadPoolDemo    {        // 用于保存每个线程的计算结果        static int[] result = new int[10];        //注意：由于WaitCallback委托的声明带有参数，        //所以将被调用的Fun方法必须带有参数，即：Fun(object obj)。        static void Fun(object obj)        {            int n = (int)obj;            //计算阶乘            int fac = 1;            for (int i = 1; i <= n; i++)            {                fac *= i;            }            //保存结果            result[n] = fac;        }        static void Main(string[] args)        {            //向线程池中排入9个工作线程            for (int i = 1; i <= 9; i++)            {                //QueueUserWorkItem()方法：将工作任务排入线程池。                ThreadPool.QueueUserWorkItem(new WaitCallback(Fun), i);                // Fun 表示要执行的方法(与WaitCallback委托的声明必须一致)。                // i   为传递给Fun方法的参数(obj将接受)。            }            //输出计算结果            for (int i = 1; i <= 9; i++)            {                Console.WriteLine("线程{0}: {0}! = {1}", i, result[i]);            }        }    }}