If you wish to expose some of the methods of your control's constituent controls
to the developer, then you will need to implement delegated methods. A delegated
method is a custom control method that acts as a wrapper for the method of an
underlying constituent control usually with a single line of code calling the
constituent control's method.
A delegated method is the only way you can let the developer access a method
of a constituent control since constituent controls are Private to the
object and so are unavailable to the developer.
You may give the delegated method the same name as the constituent control
method it implements, or you might give it a different name to show that it's
a slightly different animal.
As an example of a delegated method, you might have a
ListBox constituent control on your UserControl and
wish to allow the developer to call the ListBox Clear method
to clear out the items in the ListBox. You could provide
a custom method, ListClear, to delegate the
Clear method of the ListBox, as in Listing 13.11.
DELEGATING THE CLEAR METHOD OF THE ListBox
Public Sub ListClear()