WPF Listview Sortable Datagrid

In der <ListView /> Event GridViewColumnHeader.Click=""

        GridViewColumnHeader _lastHeaderClicked = null;
        ListSortDirection _lastDirection = ListSortDirection.Ascending;

        void GridViewColumnHeaderClickedHandler(object sender,
            RoutedEventArgs e)
        {
            var headerClicked = e.OriginalSource as GridViewColumnHeader;
            ListSortDirection direction;

            if (headerClicked != null)
            {
                if (headerClicked.Role != GridViewColumnHeaderRole.Padding)
                {
                    if (headerClicked != _lastHeaderClicked)
                    {
                        direction = ListSortDirection.Ascending;
                    }
                    else
                    {
                        if (_lastDirection == ListSortDirection.Ascending)
                        {
                            direction = ListSortDirection.Descending;
                        }
                        else
                        {
                            direction = ListSortDirection.Ascending;
                        }
                    }

                    var columnBinding = headerClicked.Column.DisplayMemberBinding as Binding;
                    var sortBy = columnBinding?.Path.Path ?? headerClicked.Column.Header as string;

                    Sort(sortBy, direction);

                    if (direction == ListSortDirection.Ascending)
                    {
                        headerClicked.Column.HeaderTemplate =
                            Resources["HeaderTemplateArrowUp"] as DataTemplate;
                    }
                    else
                    {
                        headerClicked.Column.HeaderTemplate =
                            Resources["HeaderTemplateArrowDown"] as DataTemplate;
                    }

                    // Remove arrow from previously sorted header
                    if (_lastHeaderClicked != null && _lastHeaderClicked != headerClicked)
                    {
                        _lastHeaderClicked.Column.HeaderTemplate = null;
                    }

                    _lastHeaderClicked = headerClicked;
                    _lastDirection = direction;
                }
            }
        }
        private void Sort(string sortBy, ListSortDirection direction)
        {
            ICollectionView dataView =
                CollectionViewSource.GetDefaultView(lvBinding.ItemsSource);

            dataView.SortDescriptions.Clear();
            SortDescription sd = new SortDescription(sortBy, direction);
            dataView.SortDescriptions.Add(sd);
            dataView.Refresh();
        }