此元框打印有page_attributes_meta_box 并使用以下代码生成用于选择父项的选择字段：

if ( is_post_type_hierarchical( $post->post_type ) ) :
    $dropdown_args = array(
        \'post_type\'        => $post->post_type,
        \'exclude_tree\'     => $post->ID,
        \'selected\'         => $post->post_parent,
        \'name\'             => \'parent_id\',
        \'show_option_none\' => __(\'(no parent)\'),
        \'sort_column\'      => \'menu_order, post_title\',
        \'echo\'             => 0,
    );

    $dropdown_args = apply_filters( \'page_attributes_dropdown_pages_args\', $dropdown_args, $post );
    $pages = wp_dropdown_pages( $dropdown_args );
    if ( ! empty($pages) ) :
?>
<p class="post-attributes-label-wrapper"><label class="post-attributes-label" for="parent_id"><?php _e( \'Parent\' ); ?></label></p>
<?php echo $pages; ?>

因此，假设您只需要顶级页面：

function wpse_modify_parent_dropdown_args($args, $post) {
    $args[\'depth\'] = 1;
    return $args;
}
add_filter( \'page_attributes_dropdown_pages_args\', \'wpse_modify_parent_dropdown_args\', 10, 2 );