Imports Microsoft.Office.Interop.PowerPoint
Public Class Form2
    Dim WithEvents _oPPT As New Microsoft.Office.Interop.PowerPoint.Application
 
    Private Sub Form2_Load(sender As System.Object, e As System.EventArgs) _
      Handles MyBase.Load
        Dim oPPS As Microsoft.Office.Interop.PowerPoint.Presentation = Nothing
        Dim sFilename As String = "C:\Temp\TestPresentation.ppsx"
        oPPS = _oPPT.Presentations.Open(sFilename)
    End Sub
 
    Private Sub _oPPT_SlideShowEnd(Pres As _
      Microsoft.Office.Interop.PowerPoint.Presentation) Handles _
      _oPPT.SlideShowEnd
        Me.LabelStatus.Text = "Presentation beendet" 'hier kommt die 
        ' Fehlermeldung
    End Sub
End Class

Imports Microsoft.Office.Interop.PowerPoint
Public Class Form2
    Dim WithEvents _oPPT As New Microsoft.Office.Interop.PowerPoint.Application
    Dim machIrgendwasDelegate As New MethodInvoker(AddressOf machIrgendwas) 'NEU
 
    Private Sub Form2_Load(sender As System.Object, e As System.EventArgs) _
      Handles MyBase.Load
        Dim oPPS As Microsoft.Office.Interop.PowerPoint.Presentation = Nothing
        Dim sFilename As String = "C:\Temp\TestPresentation.ppsx"
        oPPS = _oPPT.Presentations.Open(sFilename)
    End Sub
 
    Private Sub _oPPT_SlideShowEnd(Pres As _
      Microsoft.Office.Interop.PowerPoint.Presentation) Handles _
      _oPPT.SlideShowEnd
        If Me.InvokeRequired Then 'NEU
            Me.Invoke(machIrgendwasDelegate) 'NEU
        Else
            Call machIrgendwas()
        End If
    End Sub
 
    Sub machIrgendwas()
        Me.LabelStatus.Text = "Presentation beendet"
    End Sub
End Class