static AutoResetEvent myResetEvent = new AutoResetEvent(false);

public class Program
{
    const int cycleNum = 10;
    static AutoResetEvent myEvent = new AutoResetEvent(false);
    static void Main(string[] args)
    {
        ThreadPool.SetMinThreads(1, 1);
        ThreadPool.SetMaxThreads(5, 5);
        for (int i = 1; i <= cycleNum; i++)
        {
            ThreadPool.QueueUserWorkItem(new WaitCallback(testFun), i.ToString());
        }
        Console.WriteLine("主线程执行！");
        Console.WriteLine("主线程结束！");
        myEvent.WaitOne();
        Console.WriteLine("线程池终止！");
        Console.ReadKey();
    }
    public static void testFun(object obj)
    {
        Console.WriteLine(string.Format("{0}:第{1}个线程", DateTime.Now.ToString(), obj.ToString()));
        Thread.Sleep(5000);
        if (obj.ToString() == cycleNum.ToString())
        {
            myEvent.Set();
        }
    }
}