Sub Einlesen_Excel()
        With OpenFileDialog1
            .Filter = _
                        "Excel-Mappen (*.xls)|*.xls|Excel-Mappen(" & _
                        "*.xlsx)|*xlsc|Alle Dateien (*.*)|*.*"
            .FilterIndex = 1
            .InitialDirectory = "D:\Data"
            .Title = "Wir suchen eine Excel-Mappe"
            If OpenFileDialog1.ShowDialog() = DialogResult.OK Then
            End If
            Excel = .FileName
            TextBox1.Text = Excel
            Dim fi As New IO.FileInfo(Excel) 'FileEndung rauslesen
            Filename = fi.Extension
        End With
    End Sub