protected override void OnValidating(CancelEventArgs e)

Protected Overrides Sub OnValidating(e As CancelEventArgs)

Raising an event invokes the event handler through a delegate.

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