Change Style of a drawing VB API

[Redox]

Hello,

i try to change the Style of a View, but my code does not work :-(

I need to change all shaded Views of a sheet, but the following code does not do anything.
I even don't get an error?

            view2Ds = drawing.List2DViews
            For i As Integer = 0 To view2Ds.Count - 1
                view2D = view2Ds.Item(i)

                viewDisplay = view2D.Display

                If view2D.Display.Style = EpfcDisplayStyle.EpfcDISPSTYLE_SHADED Or view2D.Display.Style = EpfcDisplayStyle.EpfcDISPSTYLE_SHADED_WITH_EDGES Then
                    view2D.Display.Style = EpfcDisplayStyle.EpfcDISPSTYLE_NO_HIDDEN
                    view2D.Regenerate()
                End If

            Next

Anybody an idea?

Many thanks
Sebastian

System Creo 3.0 M40