Private Sub hbtnGrafikPlus_Click(ByVal sender As System.Object, ByVal e As _
  System.EventArgs) Handles hbtnGrafikPlus.Click
 
        Dim files() As String
 
        With of2Dialog
            .Title = "Datei zur grafischen Darstellung hinzufügen"
            .ShowDialog()
            files = Me.of2Dialog.FileNames
        End With
 
        ' Werte dem Array hinzufügen
        For Each Datei As String In Me.of2Dialog.FileNames
 
            Dim Wert As New Grafikwerte(IO.Path.GetFileName(Datei))
 
                  GrafikArray.Add(Wert)
 
        Next
 
        Werte_Eintragen()
 
        Charting()
 
        chart.Refresh()
 
 
    End Sub

Always change a running system...or you will never learn!