帝国CMS导航栏的多级菜单设置与展示，帝国CMS模板中如何调用多级菜单？

<ul>
  [e:loop={"select classid,classname from {$dbtbpre}enewsclass where bclassid=0 order by myorder",0,24,0}]
  <li><a href="<?=$bqsr[classurl]?>"><?=$bqr[classname]?></a>
    <?php
      $sub_sql = "select classid,classname from {$dbtbpre}enewsclass where bclassid={$bqr['classid']} order by myorder";
      $sub_result = mysql_query($sub_sql);
      if(mysql_num_rows($sub_result) > 0){
    ?>
    <ul>
      <?php while($sub_row = mysql_fetch_assoc($sub_result)) { ?>
        <li><a href="<?=sys_ReturnBqClassname($sub_row,9)?>"><?=$sub_row['classname']?></a></li>
      <?php } ?>
    </ul>
    <?php } ?>
  </li>
  [/e:loop]
</ul>