Walker_PageDropdown

17class Walker_PageDropdown extends Walker {18 19	/**20	 * What the class handles.21	 *22	 * @since 2.1.023	 * @var string24	 *25	 * @see Walker::$tree_type26	 */27	public $tree_type = 'page';28 29	/**30	 * Database fields to use.31	 *32	 * @since 2.1.033	 * @var string[]34	 *35	 * @see Walker::$db_fields36	 * @todo Decouple this37	 */38	public $db_fields = array(39		'parent' => 'post_parent',40		'id'     => 'ID',41	);42 43	/**44	 * Starts the element output.45	 *46	 * @since 2.1.047	 * @since 5.9.0 Renamed `$page` to `$data_object` and `$id` to `$current_object_id`48	 *              to match parent class for PHP 8 named parameter support.49	 *50	 * @see Walker::start_el()51	 *52	 * @param string  $output            Used to append additional content. Passed by reference.53	 * @param WP_Post $data_object       Page data object.54	 * @param int     $depth             Optional. Depth of page in reference to parent pages.55	 *                                   Used for padding. Default 0.56	 * @param array   $args              Optional. Uses 'selected' argument for selected page to57	 *                                   set selected HTML attribute for option element. Uses58	 *                                   'value_field' argument to fill "value" attribute.59	 *                                   See wp_dropdown_pages(). Default empty array.60	 * @param int     $current_object_id Optional. ID of the current page. Default 0.61	 */62	public function start_el( &$output, $data_object, $depth = 0, $args = array(), $current_object_id = 0 ) {63		// Restores the more descriptive, specific name for use within this method.64		$page = $data_object;65 66		$pad = str_repeat( '&nbsp;', $depth * 3 );67 68		if ( ! isset( $args['value_field'] ) || ! isset( $page->{$args['value_field']} ) ) {69			$args['value_field'] = 'ID';70		}71 72		$output .= "\t<option class=\"level-$depth\" value=\"" . esc_attr( $page->{$args['value_field']} ) . '"';73		if ( $page->ID === (int) $args['selected'] ) {74			$output .= ' selected="selected"';75		}76		$output .= '>';77 78		$title = $page->post_title;79		if ( '' === $title ) {80			/* translators: %d: ID of a post. */81			$title = sprintf( __( '#%d (no title)' ), $page->ID );82		}83 84		/**85		 * Filters the page title when creating an HTML drop-down list of pages.86		 *87		 * @since 3.1.088		 *89		 * @param string  $title Page title.90		 * @param WP_Post $page  Page data object.91		 */92		$title = apply_filters( 'list_pages', $title, $page );93 94		$output .= $pad . esc_html( $title );95		$output .= "</option>\n";96	}