protected override void OnVisibleChanged(EventArgs e)

Protected Overrides Sub OnVisibleChanged(e As EventArgs)

Raising an event invokes the event handler through a delegate.

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