Dim arr(10, 10) As System.Windows.Forms.Control
        arr(0, 0) = Button1
 
        arr(0, 1) = New ctextbox With {.Caption = "sowas"}
 
        Dim btn As System.Windows.Forms.Button = _
        CType(arr(0, 0), System.Windows.Forms.Button)
        btn.Text = "Neuer Text"
 
        Dim tb As ctextbox = CType(arr(0, 1), ctextbox)
        If tb.Caption <> "sowas" Then Stop

Public Class ctextbox
    Inherits System.Windows.Forms.TextBox
 
    Public Property Caption() As String
        Get
            Return MyBase.Text
        End Get
        Set(ByVal value As String)
            MyBase.Text = value
        End Set
    End Property
End Class