Private Sub DemoFileTime()
 
   'Eine 23er Stunden-Liste, bei der jedes Element 
   'eine Stringliste für die Dateinamen ist
   Dim hourlist As New List(Of List(Of String))
   'Listenelemente erstellen 
   For i As Integer = 0 To 23
       hourlist.Add(New List(Of String))
   Next i
 
   Dim dt As Date = CDate("28.5.2013") 'kritisches Datum
 
   Dim di As New IO.DirectoryInfo("C:\daten") 'kritischer Ordner
 
   For Each fi As IO.FileInfo In di.GetFiles
       Dim ct As Date = fi.CreationTime
       'Datum filtern
       If ct.Date = dt.Date Then
          'Zeitregister (Stunden 0-0:59:59, 1 - 1:59:59, ....)
          hourlist(ct.Hour).Add(fi.Name)
       End If
   Next fi
 
   'Ausgabe der Stundenbezogenen Dateilisten
   For i As Integer = 0 To 23
      Debug.WriteLine(String.Empty)
      Debug.WriteLine(i.ToString & " bis " & (i + 1).ToString)
      For k As Integer = 0 To hourlist(i).Count - 1
         Debug.WriteLine(hourlist(i)(k))
      Next k
   Next i
End Sub