Using <i class="emphasis">Public</i> Inheritance

Using Public Inheritance

When you make a member of a class public, there are no restrictions on its scope; it can be used by any part of your program. Public members in a base class become public members of a derived class by default. You make classes and members public with the Public keyword (see "Access Modifiers" in the In Depth section of this chapter), as I've done many places in the Inheritance example on the CD-ROM, also discussed in the In Depth section of this chapter:

Public Class Form1
    Inherits System.Windows.Forms.Form

    'Windows Form Designer generated code
    Dim spot As Dog

    Private Sub Button1_Click(ByVal sender As System.Object, _
        ByVal e As System.EventArgs) Handles Button1.Click
        spot = New Dog(Me)
        spot.Breathing()
    End Sub
End Class

Public Class Animal
    Protected MainForm As Form1
    Public Sub New(ByVal form1 As Form1)
        MainForm = form1
    End Sub

    Public Sub Breathing()
        MainForm.TextBox1.Text = "Breathing..."
    End Sub
End Class

Public Class Dog
    Inherits Animal

    Public Sub New(ByVal form1 As Form1)
        MyBase.New(form1)
    End Sub

    Public Sub Barking()
        MainForm.TextBox1.Text = "Barking..."
    End Sub
End Class