c#实现查询程序运行线程数

class Program
    {
        static void Main(string[] args)
        {
            List<Thread> list = new List<Thread>();
            for (int i = 0; i < 200; i++)
            {
                Thread t = new Thread(testThread);
                t.Start();
                list.Add(t);
            }
            Thread t3 = new Thread(() =>
            {
                while (true)
                {

                    Thread.Sleep(1000);
                    int count = 0;
                    foreach (var item in list)
                    {
                        if (item.ThreadState == ThreadState.Running)
                        {
                            count++;
                        }
                    }
                    Console.WriteLine("同时运行的" + count);
                }
            });
            t3.Start();
            Console.ReadLine();
        }

        static void testThread()
        {
            while (true)
            {
                Thread.Sleep(20);
            }
        }
    }