Simple Work Queue in C#

work_queue.cs

public delegate void DoWorkFunc<WorkItem>(WorkItem q);

public class WorkQueue<WorkItem> {
  Thread[] workers;
  DoWorkFunc<WorkItem> do_work_func;
  Queue<WorkItem> work_items;
  Semaphore n_work_items;
  Semaphore n_free_items;
  CancellationTokenSource cts;
  public WorkQueue(int n_workers, DoWorkFunc<WorkItem> do_work_func) {
    this.do_work_func = do_work_func;
    n_work_items = new Semaphore(0,         n_workers);
    n_free_items = new Semaphore(n_workers, n_workers);
    work_items = new Queue<WorkItem>(n_workers);
    workers = new Thread[n_workers-1];
    cts = new CancellationTokenSource();
    for(int i = 0; i != n_workers-1; ++i) {
      workers[i] = new Thread(DoWork);
      workers[i].Start();
      workers[i].Name = "THREAD " + (i+1);
    }
  }
  public void DoWork() {
    for(;;) {
      WorkItem item;
      WaitHandle[] handles = new WaitHandle[] {
        n_work_items,
        cts.Token.WaitHandle
      };
      int wait_result = WaitHandle.WaitAny(handles);
      if(wait_result == 1) {
        return;
      }
      lock(work_items) {
        item = work_items.Dequeue();
        do_work_func(item);
        n_free_items.Release();
      }
    }
  }
  public void AddWork(WorkItem work_item) {
    n_free_items.WaitOne();
    lock(work_items) {
      work_items.Enqueue(work_item);
      n_work_items.Release();
    }
  }
  public void WaitForCompletion() {
    for(;;) {
      lock(work_items) {
        if(work_items.Count == 0) {
          cts.Cancel();
          return;
        }
        else {
          n_work_items.WaitOne();
          WorkItem item = work_items.Dequeue();
          do_work_func(item);
          n_free_items.Release();
        }
      }
    }
  }
}