Excluding Multiple Pages with (exclude_tree)

Two things of interest to you:

1. exclude_tree does not work properly, and no fix is scheduled until Version 2.9, ref. – https://core.trac.www.ads-software.com/ticket/8683
2. exclude_tree must specify a string, ref. – https://codex.www.ads-software.com/Template_Tags/wp_list_pages

Your coding 'exclude_tree' => 31,33,18,74,); is very, very clearly wrong. What you have is an assignment of an integer 31 to exclude_tree, followed by four more array elements, presumably assigned to $args[0], [1], [2] and [3], the integers 33, 18 and 74, and a null value.

So, I would definitely try correcting that first, to see if it will work, or you are going to be hampered by the bug.

The correct coding is:
'exclude_tree' => '31,33,18,74');

You could create a work-around in the mean time, use get_col to grab the IDs for all posts from your list of parent IDs, then load them into the exclude parameter (along with the parent IDs if needed), which does still work.

You’d end up with a big exclude list, but it should work the same, it’ll just require a little more code.

[Removed to test code]

Try this (where the page IDs that you would normally pass to exclude_tree go in the first line):

$parent_pages_to_exclude = array(31,33,18,74);
foreach($parent_pages_to_exclude as $parent_page_to_exclude) {
  if ($page_exclusions) { $page_exclusions .= ',' . $parent_page_to_exclude; }
  else { $page_exclusions = $parent_page_to_exclude; }
  $descendants = get_pages('child_of=' . $parent_page_to_exclude);
  foreach($descendants as $descendant) {
    $page_exclusions .= ',' . $descendant->ID;
  }
}
wp_list_pages('title_li=&sort_column=menu_order&exclude=' . $page_exclusions);

– Tim

tim, can you clarify where that cose should be inserted for a PHP novice? It creates a parse error for me.

jtimar,

All you have to do is include Tim’s block of code in your template the same way you would the regular <?php wp_list_pages();?> tag.

It would look like this:

<?php $parent_pages_to_exclude = array(31,33,18,74);
foreach($parent_pages_to_exclude as $parent_page_to_exclude) {
if ($page_exclusions) { $page_exclusions .= ',' . $parent_page_to_exclude; }
  else { $page_exclusions = $parent_page_to_exclude; }
  $descendants = get_pages('child_of=' . $parent_page_to_exclude);
  foreach($descendants as $descendant) {
    $page_exclusions .= ',' . $descendant->ID;
  }
}
wp_list_pages('title_li=&sort_column=menu_order&exclude=' . $page_exclusions); ?>

This is very usefull!
Thanx Technokinetics

How would I use this code to display the children on one page but exclude the grandchildren of that same page?

Hello,
I’m struggling to get Technokinetics’ code working. I can’t post a link yet as the site is on a dev server. The code that I was using previously (with exclude_tree) prior to realizing it was only going to work for one post is/was:

<li class=”widget widget_text”>
<?php
global $wp_query;
$thePostID = $wp_query->post->ID;
$children = wp_list_pages(‘exclude_tree=11&title_li=&child_of=’.$thePostID.’&echo=0&depth=1′);
if ($children) { ?>

<h3>More Information</h3>
<ul id=”widgettime”><?php echo $children; ?>
<?php }
?>

Please show me how Technokinetics code fits into the above (I’ve modified Technokinetics code to include my posts here):

<?php $parent_pages_to_exclude = array(4,5,7,9,11);
foreach($parent_pages_to_exclude as $parent_page_to_exclude) {
if ($page_exclusions) { $page_exclusions .= ‘,’ . $parent_page_to_exclude; }
else { $page_exclusions = $parent_page_to_exclude; }
$descendants = get_pages(‘child_of=’ . $parent_page_to_exclude);
foreach($descendants as $descendant) {
$page_exclusions .= ‘,’ . $descendant->ID;
}
}
wp_list_pages(‘title_li=&sort_column=menu_order&exclude=’ . $page_exclusions); ?>

————-
Thanks!

for WP version 2.9.2
i have read that this is fixed, but i dont see it.
i reworked come core code, but don’t know where to submit it.
change line 2620+ of wp-includes/post.php to:

if ( !empty($exclude_tree) ) {
		$exclude_trees = preg_split('/[\s,]+/',$exclude_tree);
		if ( count($exclude_trees) ) {
			$num_pages = count($pages);
			foreach ( $exclude_trees as $tree ) {
				$exclude = (int) $tree;
				$children = get_page_children($exclude, $pages);
				$excludes = array();
				foreach ( $children as $child )
					$excludes[] = $child->ID;
				$excludes[] = $exclude;
				for ( $i = 0; $i < $num_pages; $i++ ) {
					if ( in_array($pages[$i]->ID, $excludes) )
						unset($pages[$i]);
				}
			}
		}
	}