Public Module modGlobal
    Public Interface IHöhe
        Property Höhe As Double
    End Interface
 
    Public Class Reihe(Of T As {New, IHöhe})
        Private mInternObj As New T
 
        Public Property Obj As T
            Get
                Return mInternObj
            End Get
            Set(value As T)
                mInternObj = value
            End Set
        End Property
    End Class
 
    Public Class Fläche(Of T As {New, IHöhe})
        Private mReihe As Reihe(Of T)
        Private mAnzReihen As Integer
 
        Public Sub New(ByVal R As Reihe(Of T), ByVal Anzahl As Integer)
            mReihe = R
            mAnzReihen = Anzahl
        End Sub
 
        Public ReadOnly Property Anzahl() As Integer
            Get
                Return mAnzReihen
            End Get
        End Property
 
        Public Function GetFläche() As Double
            Return m_GetFläche(mReihe.Obj, mAnzReihen)
        End Function
    End Class
 
    Public Function m_GetFläche(ByVal R As IHöhe, ByVal Länge As Double) As _
      Double
        If R Is Nothing Then Return 0
        Return R.Höhe * Länge
    End Function
 
    '========================================================================
    'Anwendungsbeispiel für m_GetFläche
    '========================================================================
    Public Class xxx
        Implements IHöhe
 
        Dim _ihöhe As Double
        Public Property Höhe As Double Implements IHöhe.Höhe
            Get
                Return _ihöhe
            End Get
            Set(value As Double)
                _ihöhe = value
            End Set
        End Property
    End Class
 
    Public Sub Demo()
        Dim r As New Reihe(Of xxx)
        r.Obj.Höhe = 500
        Dim f1 As Double = m_GetFläche(r.Obj, 250)
 
        Dim fl As New Fläche(Of xxx)(r, 10)
        Dim f2 As Double = fl.GetFläche()
    End Sub
End Module