program 21: base class construction

program to demonstrate concept of base class construction.

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Imports System.Console

Module Module1

    Sub Main()

        Dim w As New window(10, 5)

        w.drawwindow()

        Dim lb As New listbox(20, 30, "hello..!!")

        lb.drawwindow()

        Console.ReadKey()

    End Sub

End Module

Public Class window

    Private top As Integer

    Private left As Integer

    Public Sub New(ByVal top As Integer, ByVal left As Integer)

        Me.top = top

        Me.left = left

    End Sub

    Public Sub drawwindow()

        WriteLine("Drawing window at {0},{1}", top, left)

    End Sub

End Class

Public Class listbox

    Inherits window

    Public Sub New(ByVal top As Integer, ByVal left As Integer, ByVal tcontent As String)

        MyBase.New(top, left)

        mlstboxcontent = tcontent

    End Sub

    Public Shadows Sub drawwindow()

        Console.WriteLine("..........")

        MyBase.drawwindow()

        Console.WriteLine("Writing string to the listbox:{0}", mlstboxcontent)

    End Sub

    Private mlstboxcontent As String

End Class
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codestrew