Private Sub ja()
        Projekt = DataGridView1.CurrentRow.Cells(6).Value
        AddFileSecurity(Projekt, "domäne\user123", FileSystemRights.Write, _
          AccessControlType.Deny)
    End Sub
 
    Private Sub nein()
        Projekt = DataGridView1.CurrentRow.Cells(6).Value
        RemoveFileSecurity(Projekt, "domäne\user123", FileSystemRights.Write, _
          AccessControlType.Allow)
    End Sub
 
    Private Sub AddFileSecurity(ByVal Projekt As String, ByVal account As _
      String, ByVal rights As FileSystemRights, ByVal controlType As _
      AccessControlType)
        Try
            Dim fSecurity As FileSecurity = File.GetAccessControl(Projekt)
            Dim accessRule As FileSystemAccessRule = New FileSystemAccessRule( _
              account, rights, controlType)
            fSecurity.AddAccessRule(accessRule)
            File.SetAccessControl(Projekt, fSecurity)
        Catch ex As Exception
            MsgBox("Projekt ist nicht mehr vorhanden!")
        End Try
    End Sub
 
    Private Sub RemoveFileSecurity(ByVal Projekt As String, ByVal account As _
      String, ByVal rights As FileSystemRights, ByVal controlType As _
      AccessControlType)
        Try
            Dim fSecurity As FileSecurity = File.GetAccessControl(Projekt)
            fSecurity.RemoveAccessRule(New FileSystemAccessRule(account, _
              rights, controlType))
            File.SetAccessControl(Projekt, fSecurity)
        Catch ex As Exception
            MsgBox("Projekt ist nicht mehr vorhanden!")
        End Try
    End Sub