C#コンソールの下でマルチスレッドをテストする方法

class Program
{
  static void Main(string[] args)
  {
   ThreadStart num = new ThreadStart(PrintNum);
   Thread ConstrolNum = new Thread(num);
   ThreadStart str = new ThreadStart(PrintStr);
   Thread ConstrolStr = new Thread(str);
   Stopwatch watch = new Stopwatch();
   watch.Start();
   ConstrolNum.Start();
   ConstrolStr.Start();
   while (true)
   {
    if (ConstrolNum.ThreadState == System.Threading.ThreadState.Stopped && ConstrolStr.ThreadState == System.Threading.ThreadState.Stopped)
    {
     watch.Stop();
     Console.WriteLine(watch.Elapsed.TotalMilliseconds);
     break;
    }
   }
   Console.ReadKey();
  }
  private static void PrintNum()
  {
   for (int i = 1; i < 1000; i++)
   {
    Console.WriteLine(i);
   }
  }
  private static void PrintStr()
  {
   for (int i = 1; i < 1000; i++)
   {
    Console.WriteLine(" :{0}", i);
   }
  }
}