confused about wp_list_pages() function - how to display selected top pages with all their subpages

Question

I'm a bit confused about wp_list_pages() function.

Lets say I have 3 top level pages (with no parent) and each of them have some sub-pages:

• page 1 [sub-pages: 1.1, 1.2, 1.3];
• page 2 [sub-pages: 2.1, 2.2, 2.3];
• page 3 [sub-pages: 3.1, 3.2]

What I'm trying to do is to display top level pages 2 and 3 with all their subpages:

wp_list_pages( 'sort_column=menu_order&depth=0&title_li=&include=2,3' );

I have also tried so specify the depth as depth=2:

wp_list_pages( 'sort_column=menu_order&depth=2&title_li=&include=2,3' );

However, the top level pages 2 and 3 are displayed with no subpages. I'm not sure if I understood the function description correctly.

How do I achive such functionality when sub-pages can be added/deleted at any time.

Many thanks, Dasha

Answer 1

When you use include parameter of wp_list_pages you are basically telling it to only include these certain Pages in the list.

you should use exclude_tree instead, when using this parameter it will exclude a parent and all of that parent's child Pages.

so something like:

$top_pages_to_exclude = '1'; // the top page to be excluded ID, you can specify more then one '1,2,23'

$args = array(
    'sort_column' => 'menu_order',
    'depth' => 2,
    'title_li' => '',
    'exclude_tree' => $top_pages_to_exclude
);
wp_list_pages( $args );

Answer 2

Thanks to @Bainternet for pointing me to the exclude_tree, although I ended up using a bit different code.

It was important to be able to add top-level pages that don't have to appear in the menu (for example for Improved Include Page Plugin. Using the exclude_tree I would need to update the code every time a new top-level page is added.

Instead, I have an array of all top-level pages that need to appear in the menu. I then collect all their desendant pages and use wp_list_pages to display only secelted pages.

Here is the code:

<?php //main nav: use wp_list_pages to display cirtain parents pages and all thier descendant pages
$parents = array(2,3);
$children = array();
foreach($parents as $parent) {
    $child_pages = get_pages( "child_of=$parent" );
    if($child_pages){
        foreach($child_pages as $child_page){
            $children[] = $child_page->ID;
        }
    }
}
//merge $parents and $children
$menu_pages = array_merge((array)$parents, (array)$children);
$menu_pages_str = implode(",", $menu_pages); 
?>

<ul id="main-nav">
    <?php wp_list_pages( "sort_column=menu_order&title_li=&include=$menu_pages_str" ); ?>
</ul>

Also, have a look at the Codex List parent Page and all descendant Pages for more examples.