PHP SMARTY 双循环(递归)输出分类 有关问题

PHP SMARTY 双循环(递归)输出分类 问题
模版

PHP code

{foreach from=$classlist item=newsclass}
    
{$newsclass.classname}
{/foreach}

程序

PHP code

$sql = "select * from jh_newsclass where parentid = 0";
$result = $mysqli->query($sql);
while ($row = $result->fetch_row()) {
    $classlist[] = array(
        'id'=>$row[0],
        'classname'=>$row[2],
        'parentid'=>$row[1],
        'ispro'=>$row[3],    
        );
}
$result->close();
$mysqli->close();
$smarty->assign('classlist',$classlist);
$smarty->assign('webname',Webname);
$smarty->display('admin/left.htm');

这样只能输出一级分类. 我需要在一级分类下再输出二级..三级..该怎么写呀?


以前用ASP输出的效果

HTML code

              
新闻专题

+--新闻动态
+--美大专题
+--月兔专题


    
供求信息

              
产品展示

+--美大灶具
+--月图厨柜
+--集成效果

原来的ASP代码

HTML code

    
&newsclass=" target="main">

              

        

")
        while not showparentclassrs.eof

            response.Write"
"
            set temprs = conn.execute("select * from Jh_newsclass where parentid = " & showparentclassrs("id"))
            if temprs.eof and temprs.bof then
                response.Write"" & astr & tree & "" & showparentclassrs("classname")&""
            else
                response.Write astr & tree & "" & showparentclassrs("classname")
            end if
            set temprs = nothing
            response.Write"
"


            call showparentclass(astr,tree&"--",showparentclassrs("id"))
        showparentclassrs.movenext
        wend
    response.Write("