Signalling issue in MultiThreading [closed]

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I was implementing "Producer/consumer queue" from Albahari's threading article link -->

In this article's work method below, if i add a console write like Console.WriteLine("In waiting state .... 1") before _wh.WaitOne(), then Signalling don't work and Consumer thread seems to be waiting indefinitely.

void Work()
  {
    while (true)
    {
      string task = null;
      lock (_locker)
        if (_tasks.Count > 0)
        {
          task = _tasks.Dequeue();
          if (task == null) return;
        }
      if (task != null)
      {
        Console.WriteLine ("Performing task: " + task);
        Thread.Sleep (1000);  // simulate work...
      }
      else
        **Console.WriteLine("In waiting state .... 1");**
        _wh.WaitOne();         // No more tasks - wait for a signal
    }
  }

Can someone explain this behavior?

Answer 1

Because without curly braces the _wh.WaitOne isn't part of the else statement. You probably want

      else {
        Console.WriteLine("In waiting state .... 1");
        _wh.WaitOne(); 
      }