>I have a usercontrol, and internally I'm changing it's size. I then have:
>
>

>        protected override void OnResize(EventArgs e)
>        {
>            // My code here
>
>            base.OnResize(e);
>        }
>

>
>What event args is it expecting?

You usually have object Sender and EventArgs (of some kind) e. These arguments are provided to you by the event system and should be prefilled. If you want to create your own you can.