protected virtual void OnKeyUp(object sender, KeyEventArgs e)

Protected Overridable Sub OnKeyUp(sender As Object, e As KeyEventArgs)

Raising an event invokes the event handler through a delegate.

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