这是我想要制作的真实图片。

 <ul>
    <li>
        <ul>
            <li> </li>
            <li> </li>
           ###NOT HERE ###
        </ul>
     </Ii>
    ###I want to add some html here ###
</ul>

我尝试如下：

public function end_lvl( &$output, $depth = 0, $args = array() ) {
    if ( isset( $args->item_spacing ) && \'discard\' === $args->item_spacing ) {
        $t = \'\';
        $n = \'\';
    } else {
        $t = "\\t";
        $n = "\\n";
    }
    $indent = str_repeat( $t, $depth );
    $output .= "$indent".get_search_form(false)."</ul>{$n}";
}

但它在每个子菜单的末尾追加了搜索框（#####不在这里###部分）。如何实现所需的输出。有什么想法吗？

add_filter(\'wp_nav_menu_items\',\'add_search_box_to_menu\', 10, 2);
    function add_search_box_to_menu( $items, $args ) {
        if( $args->theme_location == \'primary\' )
            return $items."<li class=\'menu-header-search\'><form action=\'http://example.com/\' id=\'searchform\' method=\'get\'><input type=\'text\' name=\'s\' id=\'s\' placeholder=\'Search\'></form></li>";

        return $items;
    }