Do I need to remove event subscriptions from objects before they are orphaned?

Question

If my software has two object instances, one of which is subscribed to the events of the other. Do I need to unsubscribe them from one another before they are orphaned for t

Answer 1

You only need to unhook events if the object exposing the events is long-lived, but the object hooking the event would otherwise be short-lived (and get garbage collected fairly quickly).

In this case, failing to unhook will cause what amounts to a memory leak, because your short-lived object will not be able to be GCed -- because the event in the long-lived object holds onto a delegate, which holds a reference to the short-lived object. Since the short-lived object is still referenced by that delegate, it can't get garbage-collected.

Static events are long-lived by definition -- they live until the program exits. If you hook a static event, you definitely should unhook it when you're done.

If both objects are about to be orphaned, unhooking isn't necessary.