I have a class that is a "manager" sort of class. One of it's functions is to signal that the long running process of the class should shut down. It does this by setting a boolean called "IsStopping" in class.

public class Foo
{
    bool isStoping

    void DoWork() {
        while (!isStopping)
        {
            // do work...
        }
    }
}

Now, DoWork() was a gigantic function, and I decided to refactor it out and as part of the process broke some of it into other classes. The problem is, Some of these classes also have long running functions that need to check if isStopping is true.

public class Foo
{
    bool isStoping

    void DoWork() {
        while (!isStopping)
        {
            MoreWork mw = new MoreWork()
            mw.DoMoreWork() // possibly long running
            // do work...
        }
    }
}

What are my options here?

I have considered passing isStopping by reference, which I don't really like because it requires there to be an outside object. I would prefer to make the additional classes as stand alone and dependancy free as possible.

I have also considered making isStopping a property, and then then having it call an event that the inner classes could be subscribed to, but this seems overly complex.

Another option was to create a "Process Cancelation Token" class, similar to what .net 4 Tasks use, then that token be passed to those classes.

How have you handled this situation?

EDIT:

Also consider that MoreWork might have a EvenMoreWork object that it instantiates and calls a potentially long running method on... and so on. I guess what i'm looking for is a way to be able to signal an arbitrary number of objects down a call tree to tell them to stop what they're doing and clean up and return.