Use MustInherit to define abstract class : MustInherit « Class Module « VB.Net Tutorial

1. VB.Net Tutorial
2. Class Module
3. MustInherit

Public MustInherit Class Printable
    Public PageData As String

    Public MustOverride Sub ShowPage()

    Public Sub New(ByVal Message As String)
        PageData = Message
    End Sub

End Class

Public Class Word
    Inherits Printable

    Public Overrides Sub ShowPage()
        Console.WriteLine("word: " & PageData)
    End Sub

    Public Sub New(ByVal Message As String)
        MyBase.New(Message)
    End Sub

End Class

Public Class Text
    Inherits Printable

    Public Overrides Sub ShowPage()
        Console.WriteLine("Test: " & PageData)
    End Sub

    Public Sub New(ByVal Message As String)
        MyBase.New(Message)
    End Sub

End Class


Module Module1


    Sub Main()
        Dim WebPage As Word = New Word("word page")

        Dim MobilePage As Text = New Text("text file")

        WebPage.ShowPage()
        Console.WriteLine()
        MobilePage.ShowPage()
    End Sub

End Module

word: word page

Test: text file