Option Strict On
Imports System
Public Class Control
Public Sub New(ByVal top As Integer, ByVal left As Integer)
Me.top = top
Me.left = left
End Sub
Public Overridable Sub DrawControl( )
Console.WriteLine("Control: drawing Control at {0}, {1}", top, left)
End Sub
Protected top As Integer
Protected left As Integer
End Class
Public Class Label
Inherits Control
Public Sub New(ByVal top As Integer, ByVal left As Integer, ByVal n As String)
MyBase.New(top, left)
text = n
End Sub
Public Overrides Sub DrawControl( )
MyBase.DrawControl( )
Console.WriteLine("Writing string to the listbox: {0}", text)
End Sub
Private text As String
End Class
Public Class Button
Inherits Control
Public Sub New(ByVal top As Integer, ByVal left As Integer)
MyBase.New(top, left)
End Sub 'New
Public Overrides Sub DrawControl( )
Console.WriteLine("Drawing a button at {0}, {1}" + ControlChars.Lf, top, Left)
End Sub
End Class
Public Class Tester
Shared Sub Main( )
Dim win As New Control(1, 2)
Dim lb As New Label(3, 4, "test")
Dim b As New Button(5, 6)
win.DrawControl( )
lb.DrawControl( )
b.DrawControl( )
Dim winArray(3) As Control
winArray(0) = New Control(1, 2)
winArray(1) = New Label(3, 4, "AAA")
winArray(2) = New Button(5, 6)
Dim i As Integer
For i = 0 To 2
winArray(i).DrawControl( )
Next i
End Sub
End Class
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