protected override void OnEnter(EventArgs e)

Protected Overrides Sub OnEnter(e As EventArgs)

Raising an event invokes the event handler through a delegate.

The OnEnter method also allows derived classes to handle the event without attaching a delegate. This is the preferred technique for handling the event in a derived class.

Notes to Inheritors:

When overriding OnEnter in a derived class, be sure to call the base class's OnEnter method so that registered delegates receive the event.