Use WaitHandle in CountdownEvent

Question

I have simple application that illustrates CountdownEvent. It is fine, but I would like somehow to set WaitHandle of CountDownEvent and use it. Is it possible? How to achieve that? I suppose I should register WaitHandle and pass it to CountDownEvent?

public static CountdownEvent _countDwn = new CountdownEvent(3);

static void Main(string[] args)
{
    new Thread(say).Start("hello 1");
    new Thread(say).Start("hello 2");
    new Thread(say).Start("hello 3");
    _countDwn.Wait();

    Console.WriteLine("done");
    Console.ReadLine();   
}    

public static void Go(object data, bool timedOut)
{
    Console.WriteLine("Started - " + data);
    // Perform task...
}

public static void say(Object o)
{
    Thread.Sleep(4000);
    Console.WriteLine(o);
    _countDwn.Signal(); 
}

UPD

I would like to get something similar to sample with ManualResetEvent. No blocking wait():

static ManualResetEvent _starter = new ManualResetEvent (false);

public static void Main()
{
  RegisteredWaitHandle reg = ThreadPool.RegisterWaitForSingleObject
                             (_starter, Go, "Some Data", -1, true);
  Thread.Sleep (5000);
  Console.WriteLine ("Signaling worker...");
  _starter.Set();
  Console.ReadLine();
  reg.Unregister (_starter);    // Clean up when we’re done.
}

public static void Go (object data, bool timedOut)
{
  Console.WriteLine ("Started - " + data);
  // Perform task...
}

Answer 1

You can use the same way you use for ManualResetEvent:

 RegisteredWaitHandle reg = ThreadPool.RegisterWaitForSingleObject
                         (_countDwn.WaitHandle, Go, "Some Data", -1, true);
 /// ...

 reg.Unregister(_countDwn.WaitHandle);