public function set_sortorder($sortorder) {
        $oldorder = $this->file_record->sortorder;
        $filerecord = new stdClass;
        $filerecord->sortorder = $sortorder;
        $this->update($filerecord);
        if (!$this->is_directory()) {
            // Callback for file sort order change.
            if ($pluginsfunction = get_plugins_with_function('after_file_sorted')) {
                foreach ($pluginsfunction as $plugintype => $plugins) {
                    foreach ($plugins as $pluginfunction) {
                        $pluginfunction($this->file_record, $oldorder, $sortorder);
                    }
                }
            }
        }
    }