早上起的得早，搂了一眼线程池的内容速记下来。

        public static void Main()
        {
            // Queue the task.
            ThreadPool.QueueUserWorkItem(new WaitCallback(ThreadProc));
            ThreadPool.QueueUserWorkItem(new WaitCallback(ThreadProc2));

            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(10000);

            Console.WriteLine("Main thread exits.");

            Console.ReadLine();
        }

        // This thread procedure performs the task.
        static void ThreadProc(Object stateInfo)
        {
            // No state object was passed to QueueUserWorkItem, so
            // stateInfo is null.
            Thread.Sleep(5000);
            Console.WriteLine("1111111");
        }

        static void ThreadProc2(Object stateInfo)
        {
            // No state object was passed to QueueUserWorkItem, so
            // stateInfo is null.
            Thread.Sleep(3000);
            Console.WriteLine("222222.");
        }

 

Output:

Main thread does some work, then sleeps.
222222.
1111111
Main thread exits.