public void Main()
        {
            ThreadPool.QueueUserWorkItem(JobForAThread); // 将某工作交给线程池

        }

        void JobForAThread(object state) // 线程要执行的工作：满足 委托WaitCallback
        {
            for (int i = 1; i <= 5; i++)
            {
                Console.WriteLine("Running Thread {0},Step {1}", Thread.CurrentThread.ManagedThreadId, i);
                Thread.Sleep(500);
            }
        }

            int vWorkerThreads; 
            int vCompletionPortThreads;
            ThreadPool.GetMaxThreads(out vWorkerThreads, out vCompletionPortThreads);
            Console.WriteLine("池中辅助线程的最大数{0},池中异步 I/O 线程的最大数{1}", vWorkerThreads, vCompletionPortThreads);

        public void Main()
        {
            ThreadPool.QueueUserWorkItem(JobForAThread,"这是传递给工作内容的参数"); // 添加工作的同时，传递参数

            Console.ReadKey(); // 让主线程等待，否则“一闪而过”
        }

        void JobForAThread(object state) 
        {
            Console.WriteLine("收到信息：{0}", (string)state); // 处理传进来的数据

            for (int i = 1; i <= 5; i++)
            {               
                Console.WriteLine("Running Thread {0},Step {1}", Thread.CurrentThread.ManagedThreadId, i);
                Thread.Sleep(500);
            }
        }

        ManualResetEvent mManualEvent;

        public void Main()
        {
            mManualEvent = new ManualResetEvent(false); // 实例

            ThreadPool.QueueUserWorkItem(JobForAThread);

            Console.WriteLine("{0} 任务已经交给线程池了，但是它没有执行.", DateTime.Now.ToString("HH:mm:ss"));
            Thread.Sleep(10000); // 等待 10s
            mManualEvent.Set();  // 发出信号，让线程继续执行
           
            Console.ReadKey(); // 让主线程等待，否则“一闪而过”
        }

        void JobForAThread(object state) 
        {
            mManualEvent.WaitOne(); // 等待 “ mManualEvent.Set();” 这一句执行（发送信号）
            Console.WriteLine("{0} 现在开始执行任务啦.", DateTime.Now.ToString("HH:mm:ss"));

            for (int i = 1; i <= 5; i++)
            {               
                Console.WriteLine("Running Thread {0},Step {1}", Thread.CurrentThread.ManagedThreadId, i);
                Thread.Sleep(500);
            }
        }

        AutoResetEvent[] mAutoResetEvent;
        public void Main()
        {
            mAutoResetEvent = new AutoResetEvent[]{
                new AutoResetEvent(false), // 默认信号为 阻塞
                new AutoResetEvent(false),
                new AutoResetEvent(false)
            };

            for (int i = 0; i < 3; i++) // 创建3个工作
            {
                Thread.Sleep(1000);
                ThreadPool.QueueUserWorkItem(JobForAThread, i); 
            }
            Console.WriteLine("所有工作已经添加到池中...");
            WaitHandle.WaitAll(mAutoResetEvent); // 等待 mAutoResetEvent 中所有信号变为 继续 后，继续后面代码
            Console.WriteLine("所有工作已经完成了");

            Console.ReadKey(); // 让主线程等待，否则“一闪而过”
        }

        void JobForAThread(object state) 
        {
            int vJobIndex = (int)state;
            Console.WriteLine("Job {0} Started.", vJobIndex);
            for (int i = 1; i <= 5; i++)
            {
                Console.WriteLine("Running Thread {0},Step {1},Job {2} ", Thread.CurrentThread.ManagedThreadId, i, vJobIndex);
                Thread.Sleep(500);
            }

            mAutoResetEvent[vJobIndex].Set();
        }