VB.NET 2005 Free Training : Event Handling In Visual Basic .NET 2005 - Introduction to Event Handling, One of the most useful capabilities of the OOP Languages is their inbuilt ability to be aware of a large number of events like MouseOver, MouseClick, and so on so that we can write codes to react to any event that we are interested. This is made possible by the rich set of classes that have been built in the .NET Framework.