Zitat:

Ob man im NTFS-Dateisystem per WMI einzelne Dateien komprimiert verwalten kann, ist mir leider nicht bekannt.

Imports System.IO
 
Public Class Form1
 
    Private Const COMPRESSION_FORMAT_NONE As Short = 0
    Private Const COMPRESSION_FORMAT_LZNT1 As Short = 2
    Private Const FSCTL_SET_COMPRESSION As Integer = 639040
 
    Private Declare Function DeviceIoControl Lib "kernel32" _
              (ByVal hDevice As IntPtr, _
               ByVal dwIoControlCode As Integer, _
               ByRef lpInBuffer As Short, _
               ByVal nInBufferSize As Short, _
               ByVal lpOutBuffer As Integer, _
               ByVal nOutBufferSize As Integer, _
               ByRef lpBytesReturned As Integer, _
               ByVal lpOverlapped As IntPtr) As Boolean
 
    Private Sub CompressFile(ByVal file As String)
        Dim Size As Short = 2
        Dim ReturnedBytes As Integer
        Dim Result As Boolean
        Dim Stream As FileStream
 
        Try
            Stream = New FileStream(file, FileMode.Open, FileAccess.ReadWrite, _
              FileShare.None)
 
            Result = DeviceIoControl(Stream.Handle, _
                                                  FSCTL_SET_COMPRESSION, _
                                                  COMPRESSION_FORMAT_LZNT1, _
                                                  Size, _
                                                  0, _
                                                  0, _
                                                  ReturnedBytes, _
                                                  IntPtr.Zero)
            Stream.Close()
 
        Catch
            If Not Stream Is Nothing Then
                Stream.Close()
            End If
        End Try
 
    End Sub
 
 
    Private Sub DeCompressFile(ByVal file As String)
        Dim Size As Short = 2
        Dim ReturnedBytes As Integer
        Dim Result As Boolean
        Dim Stream As FileStream
 
        Try
            Stream = New FileStream(file, FileMode.Open, FileAccess.ReadWrite, _
              FileShare.None)
 
            Result = DeviceIoControl(Stream.Handle, _
                                                  FSCTL_SET_COMPRESSION, _
                                                  COMPRESSION_FORMAT_NONE, _
                                                  Size, _
                                                  0, _
                                                  0, _
                                                  ReturnedBytes, _
                                                  IntPtr.Zero)
            Stream.Close()
 
        Catch
            If Not Stream Is Nothing Then
                Stream.Close()
            End If
        End Try
 
    End Sub

    Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) _
      Handles Button1.Click
        CompressFile("c:\temp\test.txt")
 
        ' bzw.
 
        DeCompressFile("c:\temp\test.txt")
 
    End Sub

Dim strComputer As String = "."
Dim objWMIService As Object = GetObject("winmgmts:" & "!\\" & strComputer & _
  "\root\cimv2")
Dim colFiles As Object = objWMIService.ExecQuery _
     ("Select * from CIM_DataFile where Name = " & "'G:\\Daten\\lf2.txt'")
 
For Each objFile As Object In colFiles
    objFile.compress
Next objfile

EALA FREYA FRESENA