Question

In a webpart I have two user controls loaded. I want to be able to populate one of the controls when an event is triggered in the other control, a parameter has to be passed between the controls.

Answer 1

You could have your webpart wire the two controls together so lets assume your controls are producer and consumer.

void on_Load() {    producer.CustomEvent+=new EventHandler(consumer.HandleCustomEvent); } 

This is one of the simpler solutions however it can be brittle.