Question

If I have an application with only a few event handlers registered (and the objects using the events are not disposed until the application is closed), do I really need to worry about unregistering those handlers? The only good reason I could see is that there might be a little extra overhead if events are being fired that you dont necessarly care about (i.e you have multiple handlers registered to one event). Is there any other good reason to? Anyone run into major issues because they didnt unregister events?

Answer 1

If you have A publishing an event, and B subscribing to an event (the handler), then it is only a problem not to unsubscribe if A is going to live a lot longer than B. Basically, the event subscription means that A can still see B, so would prevent it from being garbage collected, and would still fire events on it even if you’ve forgotten about it (and perhaps Disposed() it).

For example, this is a problem if A is a static event, and your app runs for a while after B dies… ButB will live as long as A , thus B will not be garbage collected.

It is important to note, one might ask the following:

if B lives a lot longer than A, will B keep A from being garbage collected?

And the answer to that is “no”. B has no reference to A through the event; A will be collected as normal