没有具体的答案，但评论时间太长。您还可以尝试查看WordPress core本身使用的代码。我知道你说过你不能使用自动添加页面的复选框，但你可以看看它是如何使用的。在WordPress代码中进行一点挖掘（使用一个像样的文本编辑器，您应该能够在整个WordPress代码库中搜索短语），就会发现：

/**
 * Automatically add newly published page objects to menus with that as an option.
 *
 * @since 3.0.0
 * @access private
 *
 * @param string $new_status The new status of the post object.
 * @param string $old_status The old status of the post object.
 * @param object $post The post object being transitioned from one status to another.
 * @return void
 */
function _wp_auto_add_pages_to_menu( $new_status, $old_status, $post ) {
    if ( \'publish\' != $new_status || \'publish\' == $old_status || \'page\' != $post->post_type )
        return;
    if ( ! empty( $post->post_parent ) )
        return;
    $auto_add = get_option( \'nav_menu_options\' );
    if ( empty( $auto_add ) || ! is_array( $auto_add ) || ! isset( $auto_add[\'auto_add\'] ) )
        return;
    $auto_add = $auto_add[\'auto_add\'];
    if ( empty( $auto_add ) || ! is_array( $auto_add ) )
        return;

    $args = array(
        \'menu-item-object-id\' => $post->ID,
        \'menu-item-object\' => $post->post_type,
        \'menu-item-type\' => \'post_type\',
        \'menu-item-status\' => \'publish\',
    );

    foreach ( $auto_add as $menu_id ) {
        $items = wp_get_nav_menu_items( $menu_id, array( \'post_status\' => \'publish,draft\' ) );
        if ( ! is_array( $items ) )
            continue;
        foreach ( $items as $item ) {
            if ( $post->ID == $item->object_id )
                continue 2;
        }
        wp_update_nav_menu_item( $menu_id, 0, $args );
    }
}

add_action( \'transition_post_status\',     \'_wp_auto_add_pages_to_menu\', 10, 3 );