Private Sub Button5_Click(ByVal sender As System.Object, ByVal e As _
   System.EventArgs) Handles Button5.Click
        Try
            With SaveFileDialog1
                .Title = "Datei speichern"
                .InitialDirectory = Application.StartupPath
                .FileName = "Test.txt"
                .Filter = "Dateien (*.txt)|*.dat|Alle Dateien (*.*)|*.*"
                If .ShowDialog() = System.Windows.Forms.DialogResult.OK Then
                    Dim fs As New FileStream(.FileName, FileMode.Create, _
                      FileAccess.Write)
                    Dim strmWriter As New StreamWriter(fs)
                    For i As Integer = 0 To ListView1.Items.Count - 1          _
                      ' alle Zeilen (Items) der ListView
                        For j As Integer = 0 To ListView1.Items( _
                        i).SubItems.Count - 1  ' alle Spalten (SubItems) der 
                        ' ListView
                            Dim sep As String = String.Empty
                            If j > 0 Then sep = ";" ' einzelne Einträge trennen
                            strmWriter.Write(sep + ListView1.Items(i).SubItems( _
                              j).Text)
                        Next j
                        strmWriter.WriteLine()
                    Next i
                    strmWriter.Flush()
                    strmWriter.Close()
                End If
            End With
        Catch ex As Exception
            MessageBox.Show(ex.Message)
 
        End Try
        MsgBox("   !!  Fertig  !!   ")
    End Sub

 oStream = New IO.StreamWriter(sFile, True) 'anhängen