Public Class Form1

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

End Sub
Sub ForEachSubPath(ByVal StartFolder As String)
Dim sName As String
Dim FileName As String
Dim FolderName As String
Dim Dirs() As String
Dim DirsNo As Integer
Dim i As Integer

'Eventuell Backslash anhängen
If Right(StartFolder, 1) <> "C:\psordner" Then StartFolder = StartFolder & "C:\psordner"

'Alle Dateien des Verzeichnisses auflisten
sName = Dir(StartFolder & "C:\psordner")

While Len(sName) > 0
FileName = StartFolder & sName 'Filename enthält dann die aktuelle Datei

'Hier Ihren Code für jede Datei einsetzen...

sName = Dir()
End While

'Alle Unterverzeichnisse in Array einlesen
DirsNo = 0
sName = Dir(StartFolder, vbDirectory)
While Len(sName) > 0
If sName <> "." And sName <> ".." Then
DirsNo = DirsNo + 1
ReDim Preserve Dirs(DirsNo)
Dirs(DirsNo - 1) = sName
End If
sName = Dir()
End While

My.Computer.FileSystem.WriteAllText("C:\psordner\pstext.txt",
"This is new text to be added.", True)


For i = 0 To DirsNo - 1
FolderName = StartFolder & Dirs(i) & "C:\psordner"
ForEachSubPath(FolderName)

'Hier Ihren Code für jedes Verzeichnis einsetzen...
Next
End Sub

Private Sub TextBox1_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TextBox1.TextChanged
End Sub
Private Function Right(ByVal StartFolder As String, ByVal p2 As Integer) As String
Throw New NotImplementedException
End Function
End Class

'Eventuell Backslash anhängen
If Right(StartFolder, 1) <> "C:\psordner" Then StartFolder = StartFolder & "C:\psordner"

'Alle Dateien des Verzeichnisses auflisten
sName = Dir(StartFolder & "C:\psordner")