Question

I need to do some operations on a certain interval (e.g. from 5 to 5 minutes in a loop) but need to be able to fully stop the thing whenever I want (on push of a button).

I was thinking into using a Timer class but events might fire even after the timer is stopped.

How can I have some code running on a timer and still be able to immediately bring everything to a complete stop?

Just so I am properly understood: By complete stop I mean that events stop and I can dispose of objects like the timer itself etc. I am not asking how to avoid having side effects from unexpected events that are fired after the timer is stopped!

Answer 1

Answer to this question depends a lot on a type of your operations.

Best scenario is to run a thread with a loop and listen to abort event.

static AutoResetEvent abort = new AutoResetEvent();
Thread worker = new Thread(WorkerThread);

void MainThread()
{
  worker.Start();
  Thread.Sleep(30000);
  abort.Set();
}    

void WorkerThread()
{
  while(true)
  {
     if(abort.WaitOne(5000)) return;
     // DO YOUR JOB
  }
}   

When you call abort.Set() from another thread, this one will exit.

But if your code is long running, you won’t be able to exit until job is done.
To exit immediately you will have to abort thread, but this is not too wise because of resource consumption.

Alternatively, if your operation is long running (let’s say you are going through long array), you can check “abort” event state from time to time (every iteration of loop, for example) like this abort.WaitOne(0).