在wordpress中创建页面层次结构的相对列表

In wordpress I have sorted all pages in a nice hierarchy. Now I want to list the parents, relativs, children and grandchildren to the active page when I visit a page. Not the full site page hierarchy

For exemple my page hierarchy looks like this

-Parent1
  -Children1-1
  -Children1-2
    -grandchildren1-2-1
    -grandchildren1-2-2
  -Children1-3
  -Children1-4

-Parent2
  -Children2-1
  -Children2-2

-Parent3
  -Children3-1
  -Children3-2
    -grandchildren3-2-1

So if i visit page "Children2-1" i want a list(menu) thats shows only
-Parent2
  -Children2-1
  -Children2-2


And if I visit "grandchildren3-2-1" the list(menu) look like
-Parent3
  -Children3-1
  -Children3-2
     -grandchildren3-2-1

How can I manage this? ?

Use below working code. It will give you result as you want.

$parrent_pgid=$post->post_parent;

$current_pgid=$post->ID;

get_page_template_slug( $current_pgid );

?>

<div class="left_sidebar" id="pg_<?php echo $current_pgid;?>">

<?php

 if ($post->post_parent)    {
 $ancestors=get_post_ancestors($post->ID);
 $root=count($ancestors)-1;
 $parent = $ancestors[$root];
 } else {
 $parent = $post->ID;
 }

 $children = wp_list_pages("sort_column=post_title&title_li=&child_of=". $parent ."&echo=0");

   if ($children) { ?>
  <ul id="subnav">
  <?php echo $children; ?>
  </ul>
  <?php } ?>

 </div>