Dim headerClicked As GridViewColumnHeader = TryCast(e.OriginalSource, _
  GridViewColumnHeader)
                Dim PropertyName As String = _
                headerClicked.Column.Header.ToString
                Dim view As ICollectionView = _
                CollectionViewSource.GetDefaultView( _
                Me.ListviewEinträge.ItemsSource)
                Dim direction As ListSortDirection = ListSortDirection.Ascending
                Using view.DeferRefresh()
                    If view.SortDescriptions.Count > 0 Then
                        Dim currentSort As SortDescription = _
                          view.SortDescriptions(0)
                        If currentSort.PropertyName = PropertyName Then
                            If currentSort.Direction = _
                              ListSortDirection.Ascending Then
                                direction = ListSortDirection.Descending
                            Else
                                direction = ListSortDirection.Ascending
                            End If
                        End If
                        view.SortDescriptions.Clear()
                    End If
                    If Not String.IsNullOrEmpty(PropertyName) Then
                        view.SortDescriptions.Add(New SortDescription( _
                          PropertyName, direction))
                    End If
                End Using

Jedes Programm,
in das sich ein Fehler einschleichen kann,wird auch einen enthalten.