Answered Multi-Select Listbox of Child Resources?

<?php
/**
 * Supports listing out the contents of a single folder that can contain pages or 
 * folders up to 2 levels deep only, e.g. if you have a folder of pages (one page
 * for one "category") :
 *
 * Categories
 *          +--- SubCategory1
 *          |       +--- EndCategory1
 *          |       +--- EndCategory2
 *          |
 *          +--- SubCategory2   
 *          +--- SubCategory3   
 */
  
// Get top-level categories
 
$criteria = array();
$criteria['parent'] = (int) $parent;
$criteria['deleted'] = '0';
$criteria['published'] = '1';
$criteria['hidemenu'] = '1';

$query = $modx->newQuery('modResource', $criteria);

// id's that should not be included on root level
$query->where(array('id:NOT IN' => array(186,26,119)));

$resources = $modx->getCollection('modResource', $query);
 
$output = array();
 
$top_level_ids = array();
foreach ($resources as $r) {
    
    // OUTPUT LEVEL 1
    $output[] = $r->get('pagetitle') .' ('.$r->get('id').')=='.$r->get('id');
    // Get sub-levels
    if ($r->get('isfolder')) {
        $criteria['parent'] = $r->get('id');
        $query = $modx->newQuery('modResource', $criteria);
		
		// id's that should not be included on this level
		$query->where(array('id:NOT IN' => array(142,165)));

        $sub_resources = $modx->getCollection('modResource', $query);
        foreach ($sub_resources as $sr) {
            
            // OUTPUT LEVEL 2
            $output[] = '   ⌊ '.$sr->get('pagetitle').' ('.$sr->get('id').')=='.$sr->get('id'); 
            
            if ($sr->get('isfolder')) {
                $criteria['parent'] = $sr->get('id');
                $query = $modx->newQuery('modResource', $criteria);
				// id's that should not be included on this level
				$query->where(array('id:NOT IN' => array(163)));

                $sub_sub_resources = $modx->getCollection('modResource', $query);
                foreach ($sub_sub_resources as $ssr) {
                    
                    // OUTPUT LEVEL 3
                    $output[] = '       ⌊ '.$ssr->get('pagetitle').' ('.$ssr->get('id').')=='.$ssr->get('id'); 
                    
                    if ($ssr->get('isfolder')) {
                        $criteria['parent'] = $ssr->get('id');
                        $query = $modx->newQuery('modResource', $criteria);
						
						// id's that should not be included on this level
						$query->where(array('id:NOT IN' => array(171)));

                        $sub_sub_sub_resources = $modx->getCollection('modResource', $query);
                        foreach ($sub_sub_sub_resources as $sssr) {
                            
                            // OUTPUT LEVEL 4
                            $output[] = '           ⌊ '.$sssr->get('pagetitle').' ('.$sssr->get('id').')=='.$sssr->get('id'); 
                 
                        }
                    }                    
                }
            }            
        }
    }
}
 
return implode('||',$output);

@SELECT pagetitle, id FROM modx_site_content WHERE parent=35

@EVAL return '==||' . $modx->runSnippet('snippetNameHere',array('parent'=>0));

$criteria = array(
    'parent' => (int) $parent,
    'deleted' => '0',
    'published' = '1',
    'hidemenu' = '1',
);

$docs = $resource->getMany('Children');

$docIds = $modx->getChildIds($docId);