thinkPHP实现递归循环栏目并按照树形结构无限极输出的方法，thinkphp递归

private function categoryTree($parentid,$level)
//因为是本类中使用所以定于为私有函数
{
$Category= D('Category');
$result = $Category->where("`parentid`=".$parentid)->order("listorder desc,catid desc")->select();
if($result)
{
$count=count($result);//当前子栏目个数
$level++;//子栏目层级
foreach($result as $v)
{
$index++;
if($count==$index) $step="└─";
else $step="├─";
$step.=str_repeat('  ',$level-1);
$nbsp=str_repeat('   ',$level-1);
$nstr=$nbsp.$step;
if($parentid==0) $nstr='';
$v['step']=$nstr;
$newData[$v['catid']]=$v;
//echo $nstr.$v['catname']."<br />";
if($v['child']==1)//如果有子栏目
{
$newData=$newData+$this->categoryTree($v['catid'],$level);
}
}
}
return $newData;
}