public function format_link($field)
    {
        $page = $this->columns[$field]['page'] ?: './'.$field;
        $attr = $this->columns[$field]['id_field'] ?: 'id';
        $this->current_row['_link'] =
            $this->app->url($page, array($attr => $this->columns[$field]['id_value']
                ? ($this->model[$this->columns[$field]['id_value']]
                    ?: $this->current_row[$this->columns[$field]['id_value'].'_original'])
                : $this->current_id, ));

        if (!$this->current_row[$field]) {
            $this->current_row[$field] = $this->columns[$field]['descr'];
        }

        return $this->format_template($field);
    }