Show child pages when on a child page

Question

On my site I have a number of parent pages with associated child pages. How can I show all the child pages of one particular parent when a visitor is either on the parent page or one of it's children?

For example;

If someone clicks onto the "Story" parent page, they'll see a list of "story" child pages in the sidebar (As well as a link to the parent page). Then if they click through to one of those child pages, they'll still be able to see the list in the sidebar

Answer 1

    Add this code in sidebar.php.this code will help you.                    


                        global $post;
                        $parent_id  = $post->post_parent; 
                        if(!empty($parent_id)){
                        $parent_post=get_post($parent_id);
                        echo '<h1 class="entry-title">'.$parent_post->post_title.'</h1>';
                            echo '<ul>';
                            $children = wp_list_pages('title_li=&child_of=' . $parent_id . '&echo=0');
                            if ($children) {
                            echo $children;
                            echo '</ul>';
                            } 
                         } else { 
                        echo '<ul>';
                        $page =$post->ID;
                        $children = wp_list_pages('title_li=&child_of=' . $page . '&echo=0');
                            if ($children) { 
                            echo $children;
                            } 
                        echo '</ul>';
                        } 

Answer 2

Depends on how you want to do it, but you can use the Sub Pages widget plugin

http://wordpress.org/extend/plugins/subpages-widget/

It hasn't been updated for a long while, but seems to be working fine on a 3.4.2 install of WP.