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>();
             ; i < ; i++)
             {
                 Thread t = new Thread(testThread);
                 t.Start();
                 list.Add(t);
             }
             Thread t3 = new Thread(() =>
             {
                 while (true)
                 {

                     Thread.Sleep();
                     ;
                     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();
             }
         }
     }