Question

I’m trying to create a generic method which assigns (and deassigns) an event handler to an object instance’s event at runtime.

Something like:

private void MyMethod<TEventArgs>(...)
   where TEventArgs : EventArgs
{
   EventHandler<TEventArgs> eventHandler = (s, e) =>
   {
      // logic
   }

   // want to assign eventHandler to an object instance passed into this method

   // more logic

   // want to deassign eventHandler from object instance
}

Currently, I’m passing in an assignEvent and deassignEvent delegate, something like:

private void MyMethod<TEventArgs>(Action<EventHandler<TEventArgs>> assignEvent, Action<EventHandler<TEventArgs>> deassignEvent)
{
   EventHandler<TEventArgs> eventHandler = (s, e) =>
   {
      // logic
   }

   assignEvent(eventHandler);

   // more logic

   deassignEvent(eventHandler);
}

And then calling the method like so:

var myObject = new MyObject();
MyMethod<MyEventArgs>(e => myObject.MyEvent += e, e => myObject.MyEvent -= e);

This just seems really horrible though!

What other options do I have?

Answer 1

A potentially better option here is to convert this to an IObservable<T>, via using Observable.FromEvent (in the Rx Framework). This allows you to treat the event itself in a first class manner, pass it into your method, then Dispose() the subscription at the end.