<Serializable()> Public Class X
    Public Event gespeichert()
    Public Sub Speichern(ByVal obj As Object)
        Dim a As New Runtime.Serialization.Formatters.Binary.BinaryFormatter
        Dim b As New IO.FileStream("C:\X.XYZ", IO.FileMode.Create)
        a.Serialize(b, obj)
        RaiseEvent gespeichert()
    End Sub
End Class
Public Class Y
    Private WithEvents a As New X
    Public Sub Speichern() Handles a.gespeichert
        a.Speichern(Me)
    End Sub
End Class
Public Class Z
    Private WithEvents a As New X
    Private Sub Speichern() Handles a.gespeichert
        a.Speichern(Me)
    End Sub
End Class

' AUFRUF
        Dim x_ As New X
        Dim y_ As New Y
        Dim z_ As New Z
        x.Speichern(y_)
        x.Speichern(z_)