How to implement cancellable worker thread
- by Arnold Zokas
Hi,
I'm trying to implement a cancellable worker thread using the new threading constructs in System.Threading.Tasks namespace.
So far I have have come up with this implementation:
public sealed class Scheduler
{
private CancellationTokenSource _cancellationTokenSource;
public System.Threading.Tasks.Task Worker { get; private set; }
public void Start()
{
_cancellationTokenSource = new CancellationTokenSource();
Worker = System.Threading.Tasks.Task.Factory.StartNew(
() => RunTasks(_cancellationTokenSource.Token),
_cancellationTokenSource.Token
);
}
private static void RunTasks(CancellationToken cancellationToken)
{
while (!cancellationToken.IsCancellationRequested)
{
Thread.Sleep(1000); // simulate work
}
}
public void Stop()
{
try
{
_cancellationTokenSource.Cancel();
Worker.Wait(_cancellationTokenSource.Token);
}
catch (OperationCanceledException)
{
// OperationCanceledException is expected when a Task is cancelled.
}
}
}
When Stop() returns I expect Worker.Status to be TaskStatus.Canceled.
My unit tests have shown that under certain conditions Worker.Status remains set to TaskStatus.Running.
Is this a correct way to implement a cancellable worker thread?
