AddHandler (and the companion RemoveHandler) is used to add (and remove) event handlers dynamically in VB.NET
Add and remove event handlers dynamically in .NET
.NET lets you add and remove Event Handlers dynamically on the fly. Your code can start and stop handling events at any time during program execution. Also, you can tie the same code (event handler) to multiple events similar to the Handles clause in VB.NET.
The VB.NET AddHandler and RemoveHandler statements allow this behavior. Both statements take two arguments: the name of the event to handle and the name of the procedure that will handle the event.
