Imports Microsoft.Office.Interop
 
Public Class Form1
 
    Const Dateipfad As String = "C:\tmp\Test.msg"
 
    Sub ändern(Dateipfad As String, neuesDatum As Date)
        Dim sFile As String = Dateipfad
 
        ' FileInfo-Objekt erstellen
        With New System.IO.FileInfo(sFile)
            ' Datums- und Zeitangaben auslesen 
            Debug.Print("Erstellungsdatum: " & .CreationTime)
            Debug.Print("Letzter Zugriff: " & .LastAccessTime)
            Debug.Print("Letzte Änderung: " & .LastWriteTime)
 
            ' Erstellungsdatum ändern
            Dim DatumTag As Integer
 
            'DatumTag = DateTime.Parse(neuesDatum.Day).DayOfWeek
            .CreationTime = New Date(neuesDatum.Year, neuesDatum.Month, _
              neuesDatum.Day, neuesDatum.Hour, neuesDatum.Minute, _
              neuesDatum.Second)
 
            ' Datumsangabe "Letzter Zugriff" ändern
            .LastAccessTime = neuesDatum ' New Date(2009, 5, 16, 13, 12, 11)
 
            ' Datum "Letzte Änderung" ändern
            .LastWriteTime = neuesDatum ' New Date(2009, 5, 17, 13, 12, 11)
        End With
    End Sub
 
    Private Sub Button2_Click(sender As System.Object, e As System.EventArgs) _
      Handles Button2.Click
        Dim objOutlook As Outlook.Application
        Dim objOutlookItem As Outlook.MailItem
 
        Dim NeuesDatum As Date
 
          ' Erzeugen...
 
        objOutlook = New Outlook.Application
 
        ' Check...
 
        If Not objOutlook Is Nothing Then
 
            '   Ab hier könntest Du eine Schleife draus machen,
            '   um die Dateien alle einzulesen
            '
            '   Mail öffnen...
            objOutlookItem = CType(objOutlook.Session.OpenSharedItem( _
              Dateipfad), Outlook.MailItem) 'strPath & "\" & strFile)
 
            '   Check...
            If Not objOutlookItem Is Nothing Then
 
                '     Auslesen...
                'MsgBox "Body: " & objOutlookItem.Body
                'MsgBox "CreationTime: " & objOutlookItem.CreationTime
                'MsgBox "DeferredDeliveryTime: " & 
                ' objOutlookItem.DeferredDeliveryTime
                MsgBox("ReceivedTime: " & objOutlookItem.ReceivedTime)
                'MsgBox "ReminderTime: " & objOutlookItem.ReminderTime
                MsgBox("SenderName: " & objOutlookItem.SenderName)
                MsgBox("SenderEmailAddress: " & _
                  objOutlookItem.SenderEmailAddress)
                MsgBox("Subject: " & objOutlookItem.Subject)
                NeuesDatum = objOutlookItem.ReceivedTime
 
                '     Schließen...
                ' Hie scheint es dran zu liegen
                'objOutlookItem.Close(Outlook.OlInspectorClose.olDiscard) ' _
                  Close(olDiscard) ' 1 = Discard = Verwerfen
                'Outlook.Application.close()
                releaseObj(objOutlookItem)
 
            End If
 
            '   Zurücksetzen...
            objOutlookItem = Nothing
 
            '
            '   Hier wäre das Ende der Schleife
            '
 
            '   Abschließen schließen...
            objOutlook.Quit()
 
        End If
 
        ' Aufräumen...
        objOutlook = Nothing
 
 
        Try
 
        Catch ex As Exception
 
        End Try
 
        Call ändern(Dateipfad, NeuesDatum)
    End Sub
 
    Private Sub releaseObj(objOutlookItem As Outlook.MailItem)
        Throw New NotImplementedException
    End Sub
 
End Class

Imports Microsoft.Win32.SafeHandles
Imports System
Imports System.Runtime.InteropServices
Class cls_Outlook
    Implements IDisposable
 
    Private disposed As Boolean = False
    Private handle As SafeHandle = New SafeFileHandle(IntPtr.Zero, True)
 
    Public Sub Dispose()
        Dispose(True)
        GC.SuppressFinalize(Me)
    End Sub
 
    Protected Overridable Sub Dispose(ByVal disposing As Boolean)
        If disposed Then Return
 
        If disposing Then
            handle.Dispose()
        End If
 
        disposed = True
    End Sub
    Public Sub ReleaseObj(ByVal obj As Object)
        Try
 
            System.Runtime.InteropServices.Marshal.ReleaseComObject(obj)
        Catch
        Finally
            obj = Nothing
        End Try
    End Sub
End Class