How to cancel a task or terminate the task execution instantly? - c#-4.0

Question

I have a windows service developed in C#. On it's Start method I have a initialization such as:
Task _backgroundTask = null;
CancellationTokenSource _backgroundCancellationSource = null;
protected override void OnStart(string[] args)
{
......
_backgroundCancellationSource = new CancellationTokenSource();
CancellationToken token = backgroundCancellationSource.Token;
_backgroundTask = new Task(() => BackgroundFoldersProcessing(token), token, TaskCreationOptions.LongRunning);
.......
}
Now the method BackgroundFoldersProcessing looks like this:
void BackgroundFoldersProcessing(CancellationToken token)
{
while (true)
{
try
{
if (token.IsCancellationRequested)
{
return;
}
DoSomeWork()
}
catch (Exception ex)
{
.........
}
}
}
Now, the Stop method is as follows:
protected override void OnStop()
{
.................
_backgroundCancellationSource.Cancel();
_backgroundTask.Wait();
_backgroundCancellationSource.Dispose();
_backgroundTask.Dispose();
_backgroundTask = null;
_backgroundCancellationSource = null;
.................
}
Now the problem is when I try to stop the service in a middle of processing, the Wait method of _backgroundTask would not stop the service until and unless the DoSomeWork() method inside the BackgroundFoldersProcessing gets completed, the Windows Service would not stop.
Is there any way, though which I can stop the service and the execution of _backgroundTask would be terminated, even though the DoSomeWork() method gets completed/executed or not? I have also tried token.ThrowIfCancellationRequested() in BackgroundFoldersProcessing method, but that also did not worked. I want that whenever I try to Stop the service from Service Control Manager (SCM), the service should be stopped immediately and the __backgroundTask should stop executing the BackgroundFoldersProcessing method and be terminated as well. How can I achieve this?

Answer 1

You can try use ThreadAbortException:
defining the thread:
ThreadStart threadDelegate = new ThreadStart(BackgroundFoldersProcessing);
Thread thread_ = new Thread(threadDelegate);
thread_.Start();
Add catch to BackgroundFoldersProcessing
catch (ThreadAbortException e)
{
return;
}
and when you want to shut it down use:
thread_.Abort();
thread_.Join();
Then when Abort() will be called ThreadAbortException will be thrown.