One of the main breakthrough differences that made PC's different from mainframes (Trust me on this. I worked on mainframes for years.) is the change from procedural programming to event-driven programming. VB.NET is completely event-driven. In fact, the original Visual Basic has a great claim to the honor of being the programming language that brought event-driven programming to the mainstream.
Since triggering events is so important, you should be able to do it from an inherited class ... but you can't. Not directly, at least. But you can do it indirectly. A new Quick Tip on the site explains how.