Question

I am adding a sub menu to an “About us” section and would like the sub menu to appear on all of its sub sections as well.

Instead of creating an if statement with each subpage added to the if statement manually is there a way to display the contents of the custom list so the if statement updates itself when new sections are added to the sub menu?

eg

$about_sub_menu_contents= something snazzy to display the menu contents;
    if($about_sub_menu_contents){
        wp_nav_menu('menu=about_sub_menu'); 
    }

I want to avoid having to add every subpage to the if statement for the menu to appear on that page.

Answer 1

<?php
    $ancestors = get_post_ancestors($post);
    if (is_page(123) || in_array(123,$ancestors)) {
        wp_nav_menu('menu=about_sub_menu');
    }
?>

Where 123 is the post-ID of the parent page (the “About us”, in your case).