Private Sub SplitFile()
 
   Dim lines As New List(Of String), line As String = ""
   Dim outpath As String = "C:\daten", outfile As String = ""  'Zielpfad 
 
   Using sr As New IO.StreamReader("C:\Daten\splitfile.txt") 'Datendatei
      While Not sr.EndOfStream
         line = sr.ReadLine
         lines.Add(line)
 
         If line.StartsWith("PG_Bezeichnung".ToUpper) Then
            Dim filename As String = _
               line.Substring(line.IndexOf("=") + 1) & ".txt"
            outfile = IO.Path.Combine(outpath, filename)
         End If
 
         If Not outfile = "" Then
            If line.StartsWith("[Hauptprogramm]".ToUpper) Then
               IO.File.WriteAllLines(outfile, lines)
               lines.Clear()
               outfile = ""
            End If
         End If
      End While
  End Using
 
  If Not lines.Count = 0 And Not outfile = "" Then
     IO.File.WriteAllLines(outfile, lines)
  End If
 
End Sub