Imports System
Namespace CompVB
Public Class Top
End Class
Public Class Middle
Inherits Top
End Class
Public Class Bottom
Inherits Middle
End Class
Public Class Up
Public Sub cv(ByVal t as Top)
Console.WriteLine ("cv(Top)
in Up using Visual Basic!")
End Sub
Public Sub ctv(ByVal t as Bottom)
Console.WriteLine ("ctv(Bottom)
in Up using Visual Basic!")
End Sub
End Class
End Namespace
-- ClientVBVB
Option Explicit
Option Strict
Imports System
Imports System.Collections
Imports CompVB
Public Module modmain
Public Class Down
Inherits Up
Overloads Public Sub cv(ByVal t as Middle)
Console.WriteLine ("cv(Middle)
in Down using Visual Basic!")
End Sub
Overloads Public Sub ctv(ByVal t as Middle)
Console.WriteLine ("ctv(Middle)
in Down using Visual Basic!")
End Sub
End Class
'The main entry point for the application
Sub Main()
Dim d As Down
Console.WriteLine("-- Calls VB from VB --")
Dim u As Up
Dim ud As Up
d = New Down
u = New Up
ud = New Down
u.cv(New Top)
u.cv(New Middle)
u.cv(New Bottom)
'u.ctv(New Top)
Console.WriteLine("Compilation error")
'u.ctv(New Middle)
Console.WriteLine("Compilation error")
u.ctv(New Bottom)
Console.WriteLine(" Down d")
d.cv(New Top)
d.cv(New Middle)
d.cv(New Bottom)
'd.ctv(New Top)
Console.WriteLine("Compilation error")
d.ctv(New Middle)
d.ctv(New Bottom)
Console.WriteLine(" Up ud")
ud.cv(New Top)
ud.cv(New Middle)
ud.cv(New Bottom)
'ud.ctv(New Top)
Console.WriteLine("Compilation error")
'ud.ctv(New Middle)
Console.WriteLine("Compilation error")
ud.ctv(New Bottom)
End Sub
End Module
-- Calls VB from VB --
cv(Top) in Up using Visual Basic!
cv(Top) in Up using Visual Basic!
cv(Top) in Up using Visual Basic!
Compilation error
Compilation error
ctv(Bottom) in Up using Visual Basic!
Down d
cv(Top) in Up using Visual Basic!
cv(Middle) in Down using Visual Basic!
cv(Middle) in Down using Visual Basic!
Compilation error
ctv(Middle) in Down using Visual Basic!
ctv(Bottom) in Up using Visual Basic!
Up ud
cv(Top) in Up using Visual Basic!
cv(Top) in Up using Visual Basic!
cv(Top) in Up using Visual Basic!
Compilation error
Compilation error
ctv(Bottom) in Up using Visual Basic!