I succeeded in this, but it is a mess. Basically, the walker should have the following parameters:
$this->db_fields['parent'] = 'post_parent';
$this->db_fields['id'] = 'ID';
But, to get that in place, you need to rip out the existing metabox callback, copy it, change one line so you get an extra filter, and place it back. Then you can pass your own walker that has these parameters set.
add_filter( 'admin_head-nav-menus.php', 'wpse2770_admin_head_nav_menus' );
function wpse2770_admin_head_nav_menus()
{
// Hijack "Pages" meta box callback with one that has an extra filter for the walker class
$GLOBALS['wp_meta_boxes']['nav-menus']['side']['default']['add-page']['callback'] = 'wpse2770_wp_nav_menu_item_post_type_meta_box';
// Since Walker_Nav_Menu_Checklist is not always available, we create this class in this function (didn't even know that was possible...)
class WPSE2770_Walker_Nav_Menu_Checklist extends Walker_Nav_Menu_Checklist
{
public function __construct()
{
$this->db_fields['parent'] = 'post_parent';
$this->db_fields['id'] = 'ID';
}
}
}
add_filter( 'wp_nav_menu_item_post_type_meta_box_walker', 'wpse2770_wp_nav_menu_item_post_type_meta_box_walker', 10, 3 );
function wpse2770_wp_nav_menu_item_post_type_meta_box_walker( $walker, $post_type, $context )
{
if ( 'page' == $post_type && 'view-all' == $context ) {
$walker="WPSE2770_Walker_Nav_Menu_Checklist";
}
return $walker;
}
function wpse2770_wp_nav_menu_item_post_type_meta_box( $object, $post_type ) {
global $_nav_menu_placeholder, $nav_menu_selected_id;
$post_type_name = $post_type['args']->name;
// paginate browsing for large numbers of post objects
$per_page = 50;
$pagenum = isset( $_REQUEST[$post_type_name . '-tab'] ) && isset( $_REQUEST['paged'] ) ? absint( $_REQUEST['paged'] ) : 1;
$offset = 0 < $pagenum ? $per_page * ( $pagenum - 1 ) : 0;
$args = array(
'offset' => $offset,
'order' => 'ASC',
'orderby' => 'title',
'posts_per_page' => $per_page,
'post_type' => $post_type_name,
'suppress_filters' => true,
'update_post_term_cache' => false,
'update_post_meta_cache' => false
);
if ( isset( $post_type['args']->_default_query ) )
$args = array_merge($args, (array) $post_type['args']->_default_query );
// @todo transient caching of these results with proper invalidation on updating of a post of this type
$get_posts = new WP_Query;
$posts = $get_posts->query( $args );
if ( ! $get_posts->post_count ) {
echo '<p>' . __( 'No items.' ) . '</p>';
return;
}
$post_type_object = get_post_type_object($post_type_name);
$num_pages = $get_posts->max_num_pages;
$page_links = paginate_links( array(
'base' => add_query_arg(
array(
$post_type_name . '-tab' => 'all',
'paged' => '%#%',
'item-type' => 'post_type',
'item-object' => $post_type_name,
)
),
'format' => '',
'prev_text' => __('«'),
'next_text' => __('»'),
'total' => $num_pages,
'current' => $pagenum
));
if ( !$posts )
$error="<li id="error">". $post_type['args']->labels->not_found .'</li>';
$walker="Walker_Nav_Menu_Checklist";
$current_tab = 'most-recent';
if ( isset( $_REQUEST[$post_type_name . '-tab'] ) && in_array( $_REQUEST[$post_type_name . '-tab'], array('all', 'search') ) ) {
$current_tab = $_REQUEST[$post_type_name . '-tab'];
}
if ( ! empty( $_REQUEST['quick-search-posttype-' . $post_type_name] ) ) {
$current_tab = 'search';
}
$removed_args = array(
'action',
'customlink-tab',
'edit-menu-item',
'menu-item',
'page-tab',
'_wpnonce',
);
?>
<div id="posttype-<?php echo $post_type_name; ?>" class="posttypediv">
<ul id="posttype-<?php echo $post_type_name; ?>-tabs" class="posttype-tabs add-menu-item-tabs">
<li <?php echo ( 'most-recent' == $current_tab ? ' class="tabs"' : '' ); ?>><a class="nav-tab-link" href="https://wordpress.stackexchange.com/questions/2770/<?php if ( $nav_menu_selected_id ) echo esc_url(add_query_arg($post_type_name ."-tab', 'most-recent', remove_query_arg($removed_args))); ?>#tabs-panel-posttype-<?php echo $post_type_name; ?>-most-recent"><?php _e('Most Recent'); ?></a></li>
<li <?php echo ( 'all' == $current_tab ? ' class="tabs"' : '' ); ?>><a class="nav-tab-link" href="https://wordpress.stackexchange.com/questions/2770/<?php if ( $nav_menu_selected_id ) echo esc_url(add_query_arg($post_type_name ."-tab', 'all', remove_query_arg($removed_args))); ?>#<?php echo $post_type_name; ?>-all"><?php _e('View All'); ?></a></li>
<li <?php echo ( 'search' == $current_tab ? ' class="tabs"' : '' ); ?>><a class="nav-tab-link" href="https://wordpress.stackexchange.com/questions/2770/<?php if ( $nav_menu_selected_id ) echo esc_url(add_query_arg($post_type_name ."-tab', 'search', remove_query_arg($removed_args))); ?>#tabs-panel-posttype-<?php echo $post_type_name; ?>-search"><?php _e('Search'); ?></a></li>
</ul>
<div id="tabs-panel-posttype-<?php echo $post_type_name; ?>-most-recent" class="tabs-panel <?php
echo ( 'most-recent' == $current_tab ? 'tabs-panel-active' : 'tabs-panel-inactive' );
?>">
<ul id="<?php echo $post_type_name; ?>checklist-most-recent" class="categorychecklist form-no-clear">
<?php
$recent_args = array_merge( $args, array( 'orderby' => 'post_date', 'order' => 'DESC', 'posts_per_page' => 15 ) );
$most_recent = $get_posts->query( $recent_args );
$args['walker'] = new $walker;
echo walk_nav_menu_tree( array_map('wp_setup_nav_menu_item', $most_recent), 0, (object) $args );
?>
</ul>
</div><!-- /.tabs-panel -->
<div class="tabs-panel <?php
echo ( 'search' == $current_tab ? 'tabs-panel-active' : 'tabs-panel-inactive' );
?>" id="tabs-panel-posttype-<?php echo $post_type_name; ?>-search">
<?php
if ( isset( $_REQUEST['quick-search-posttype-' . $post_type_name] ) ) {
$searched = esc_attr( $_REQUEST['quick-search-posttype-' . $post_type_name] );
$search_results = get_posts( array( 's' => $searched, 'post_type' => $post_type_name, 'fields' => 'all', 'order' => 'DESC', ) );
} else {
$searched = '';
$search_results = array();
}
?>
<p class="quick-search-wrap">
<input type="text" class="quick-search input-with-default-title" title="<?php esc_attr_e('Search'); ?>" value="<?php echo $searched; ?>" name="quick-search-posttype-<?php echo $post_type_name; ?>" />
<img class="waiting" src="<?php echo esc_url( admin_url( 'images/wpspin_light.gif' ) ); ?>" alt="" />
<?php submit_button( __( 'Search' ), 'quick-search-submit button-secondary hide-if-js', 'submit', false ); ?>
</p>
<ul id="<?php echo $post_type_name; ?>-search-checklist" class="list:<?php echo $post_type_name?> categorychecklist form-no-clear">
<?php if ( ! empty( $search_results ) && ! is_wp_error( $search_results ) ) : ?>
<?php
$args['walker'] = new $walker;
echo walk_nav_menu_tree( array_map('wp_setup_nav_menu_item', $search_results), 0, (object) $args );
?>
<?php elseif ( is_wp_error( $search_results ) ) : ?>
<li><?php echo $search_results->get_error_message(); ?></li>
<?php elseif ( ! empty( $searched ) ) : ?>
<li><?php _e('No results found.'); ?></li>
<?php endif; ?>
</ul>
</div><!-- /.tabs-panel -->
<div id="<?php echo $post_type_name; ?>-all" class="tabs-panel tabs-panel-view-all <?php
echo ( 'all' == $current_tab ? 'tabs-panel-active' : 'tabs-panel-inactive' );
?>">
<?php if ( ! empty( $page_links ) ) : ?>
<div class="add-menu-item-pagelinks">
<?php echo $page_links; ?>
</div>
<?php endif; ?>
<ul id="<?php echo $post_type_name; ?>checklist" class="list:<?php echo $post_type_name?> categorychecklist form-no-clear">
<?php
// WPSE 2770: And this is the filter we want to add!
$walker = apply_filters( 'wp_nav_menu_item_post_type_meta_box_walker', $walker, $post_type_name, 'view-all' );
$args['walker'] = new $walker;
// if we're dealing with pages, let's put a checkbox for the front page at the top of the list
if ( 'page' == $post_type_name ) {
$front_page="page" == get_option('show_on_front') ? (int) get_option( 'page_on_front' ) : 0;
if ( ! empty( $front_page ) ) {
$front_page_obj = get_post( $front_page );
$front_page_obj->_add_to_top = true;
$front_page_obj->label = sprintf( _x('Home: %s', 'nav menu front page title'), $front_page_obj->post_title );
array_unshift( $posts, $front_page_obj );
} else {
$_nav_menu_placeholder = ( 0 > $_nav_menu_placeholder ) ? intval($_nav_menu_placeholder) - 1 : -1;
array_unshift( $posts, (object) array(
'_add_to_top' => true,
'ID' => 0,
'object_id' => $_nav_menu_placeholder,
'post_content' => '',
'post_excerpt' => '',
'post_title' => _x('Home', 'nav menu home label'),
'post_type' => 'nav_menu_item',
'type' => 'custom',
'url' => home_url("https://wordpress.stackexchange.com/"),
) );
}
}
$args['walker']->db_fields['parent'] = 'post_parent';
$checkbox_items = walk_nav_menu_tree( array_map('wp_setup_nav_menu_item', $posts), 0, (object) $args );
if ( 'all' == $current_tab && ! empty( $_REQUEST['selectall'] ) ) {
$checkbox_items = preg_replace('/(type=(.)checkbox(\2))/', '$1 checked=$2checked$2', $checkbox_items);
}
echo $checkbox_items;
?>
</ul>
<?php if ( ! empty( $page_links ) ) : ?>
<div class="add-menu-item-pagelinks">
<?php echo $page_links; ?>
</div>
<?php endif; ?>
</div><!-- /.tabs-panel -->
<p class="button-controls">
<span class="list-controls">
<a href="<?php
echo esc_url(add_query_arg(
array(
$post_type_name . '-tab' => 'all',
'selectall' => 1,
),
remove_query_arg($removed_args)
));
?>#posttype-<?php echo $post_type_name; ?>" class="select-all"><?php _e('Select All'); ?></a>
</span>
<span class="add-to-menu">
<img class="waiting" src="<?php echo esc_url( admin_url( 'images/wpspin_light.gif' ) ); ?>" alt="" />
<input type="submit"<?php disabled( $nav_menu_selected_id, 0 ); ?> class="button-secondary submit-add-to-menu" value="<?php esc_attr_e('Add to Menu'); ?>" name="add-post-type-menu-item" id="submit-posttype-<?php echo $post_type_name; ?>" />
</span>
</p>
</div><!-- /.posttypediv -->
<?php
}