How should I inherit IDisposable?

Question

Class names have been changed to protect the innocent.

If I have an interface named ISomeInterface. I also have classes that inherit the interface, FirstClass

Answer 1

If you want all your code to deal with ISomeInterfaces generically, then yes they should all be disposable.

If not, then the code that creates FirstClass should dispose it:

using (FirstClass foo = new FirstClass()) {
    someObjectThatWantsISomeInterface.Act(foo);
}

otherwise, you could always use something like this extension method:

public static void DisposeIfPossible(this object o) {
    IDisposable disp = o as IDisposable;
    if (disp != null)
        disp.Dispose();
}

// ...
someObject.DisposeIfPossible(); // extension method on object

I should also mention that I would prefer a template base class approach to this. I stubbed this out in this blog on building disposable things properly.