您好，我想创建一个自定义导航菜单，需要创建div容器来保存子菜单集。换句话说，我想这样做：

  <ul class="left_menu">
     <li class="menu_item droped">
        <a class="top_link" href="#">Kurumsal</a>

     <div class="dropdown">
          <ul>
            <li><a href="#">Hakkımızda</a></li>
            <li><a href="#">Misyon Vizyon</a></li>
            <li><a href="#">Satın Alma</a></li>
            <li><a href="#">Kariye</a></li>
            <li><a href="#">Bayilik Başvurusu</a></li>

          </ul>
        </div>
      </li>

      <li class="menu_item droped">
        <a class="top_link" href="#/">Ürünlerimiz</a>

        <div class="dropdown">
          <ul>
            <li><a href="#">İnce Taneli Kumlar</a></li>
            <li><a href="#">İri Taneli Kumlar</a></li>
            <li><a href="#">Yalıtım Malzemeleri</a></li>
            <li class="last"><a href="#">Yapı Kimyasalları</a></li>
          </ul>
        </div>

      </li>
</ul>

如何将其添加到wp\\U nav\\U菜单功能中？是否在函数中添加过滤器。php，还是我要创建一个单独的php文件来实现这一点？

如有任何有益的建议，将不胜感激。

<?php

class wpse_112127_walker extends Walker_Nav_Menu {

    function start_lvl( &$output, $depth ) {
        $indent = str_repeat("\\t", $depth);
        $output .= "\\n" . $indent . \'<div class="dropdown"><ul>\' . "\\n";
    }

    function end_lvl( &$output, $depth = 0, $args = array() ) {
        $indent = str_repeat("\\t", $depth);
        $output .= "$indent</ul></div>\\n";
    }
}

wp_nav_menu( array( \'walker\' => new wpse_112127_walker ) );