Question

I was wondering if this actually worked ?

private void RegisterKeyChanged(T item) 
{
    item.OnKeyChanged += (o, k) => ChangeItemKey((T)o, k);
}

private void UnRegisterKeyChanged(T item) 
{
    item.OnKeyChanged -= (o, k) => ChangeItemKey((T)o, k);
}

How does the compiler know that the event handlers are the same ? Is this even recommended?

Answer 1

There’s an MSDN page that talks about this:

How to Subscribe to and Unsubscribe from Events

Note in particular:

If you will not have to unsubscribe to [sic]
an event later, you can use the
addition assignment operator (+=) to
attach an anonymous method to the
event.

And also:

It is important to notice that you
cannot easily unsubscribe from an
event if you used an anonymous
function to subscribe to it. To
unsubscribe in this scenario, it is
necessary to go back to the code where
you subscribe to the event, store the
anonymous method in a delegate
variable, and then add the delegate to
the event . In general, we recommend
that you do not use anonymous
functions to subscribe to events if
you will have to unsubscribe from
the event at some later point in your
code.