Garbage collection when using anonymous delegates for event handling

Question

UPDATE

I have combined various answers from here into a \'definitive\' answer on a new question.

Original question

Answer 1

Building further on Egor's answer, I wanted to try and build a version where I didn't have to determine in advance which event I want to attach to.

I've only managed to make it work with generic event handlers: for 'standard' event handlers (eg. FormClosingEventHandler), it's a bit tricky, because you can't have a type constraint where T : delegate (unless your name ends with Pony).

private static void SetAnyGenericHandler(
     Action> add,     //to add event listener to publisher
     Action> remove,  //to remove event listener from publisher
     S subscriber,                    //ref to subscriber (to pass to consume)
     Action consume)            //called when event is raised*
         where T : EventArgs 
         where S : class
{
    var subscriber_weak_ref = new WeakReference(subscriber);
    EventHandler handler = null;
    handler = delegate(object sender, T e)
    {
        var subscriber_strong_ref = subscriber_weak_ref.Target as S;
        if(subscriber_strong_ref != null)
        {
            Console.WriteLine("New event received by subscriber");
            consume(subscriber_strong_ref, e);
        }
        else
        {
            remove(handler);
            handler = null;
        }
    };
    add(handler);
}

(*I did try EventHandler consume here, but the calling code gets ugly because you have to cast s to Subscriber in the consume lambda.)

Calling code example, taken from example above:

SetAnyGenericHandler(
    h => publisher.EnabledChanged += h, 
    h => publisher.EnabledChanged -= h, 
    subscriber, 
    (Subscriber s, ValueEventArgs e) => s.Enabled = e.Value);

Or, if you prefer

SetAnyGenericHandler>(
    h => publisher.EnabledChanged += h, 
    h => publisher.EnabledChanged -= h, 
    subscriber, 
    (s, e) => s.Enabled = e.Value);

It would be nice to be able to pass in the Event as just one parameter, but you can't access add/remove from an event any more than you can access get/set from a property (without doing yucky reflexion stuff, I think).