Open sDN$ For Input As fn%
Open sDN$ For Append As fn%
Open sDN$ For Output As fn%
 
Close(fn%)

      Dim Filename As String = "C:\Test\Testfile.txt", _
            encoding As System.Text.Encoding = System.Text.Encoding.UTF8
 
      Dim contents() As String = System.IO.File.ReadAllLines(Filename, encoding)
 
      System.IO.File.AppendAllLines(Filename, contents, encoding)
 
      System.IO.File.WriteAllLines(Filename, contents, encoding)

    Function DateiExists(ByVal sDN As String)
 
        Dim fn As Integer
 
        fn% = FreeFile()
        On Error GoTo DateiExists_DoesNot
        FileOpen(fn%, sDN, OpenMode.Input)
        FileClose(fn%)
        DateiExists = True
        GoTo DateiExists_Exit
 
DateiExists_DoesNot:
        DateiExists = False
        Resume DateiExists_Exit
 
DateiExists_Exit:
    End Function