本文以实例描述了ThinkPHP采用<volist>标签实现三级循环代码，具体操作步骤如下：

1. 三级循环需要三维数组，实现代码如下：

function MakeTree($pid,$level) { $map['pid'] = $pid; $map['level'] = $level; $result = $this->where($map)->order('rank ASC')->findall(); if($result){ foreach ($result as $key => $value){ $title = $value['alias']; $list[$title]['id'] = $value['id']; $list[$title]['pid'] = $value['pid']; $list[$title]['alias']= $value['alias']; $list[$title]['title'] = $value['title']; $list[$title]['level'] = $value['level']; $list[$title]['state'] = $value['state']; $list[$title]['rank'] = $value['rank']; if($value['level']<=3){ $list[$title]['child'] = $this->_MakeSonTree($value['id']); } } } return $list; } function _MakeSonTree($pid) { $map['pid'] = $pid; $result = $this->where($map)->order('rank ASC')->findall(); if($result){ foreach ($result as $key => $value){ $title = $value['alias']; $list[$title]['id']= $value['id']; $list[$title]['pid']= $value['pid']; $list[$title]['alias']= $value['alias']; $list[$title]['title'] = $value['title']; $list[$title]['level'] = $value['level']; $list[$title]['state'] = $value['state']; $list[$title]['rank'] = $value['rank']; if($this->haschild($value['id'])){ //先判断是否有第三级子类,最后的数组形如$result['child']['grandchild']; $list[$title]['grandchild']=$this->_MakeSonTree($value['id']); } } } return $list; } function haschild($id){ $result=D('LearningChannel')->where("pid=".$id)->find(); if($result){ return true; } else return false; }

2.绑定volist标签：

$result=D('Learning') ->MakeTree(0,1); //dump($result); $this->assign('list',$result);

3.模板部分：

<select name="category" id="select"> <volist name="list" id="vo"> <option name="cid" value="{$vo.id}" <eq name="vo.id" value="getid">selected</eq> >{$vo.alias}</option> <volist name="vo['child']" id="child"> <option name="cid" value="{$child.id}" <eq name="child.id" value="getid">selected</eq> >--{$child.alias}</option> <volist name="child['grandchild']" id="grand"> <option name="cid" value="{$grand.id}" <eq name="grand.id" value="getid">selected</eq> >---{$grand.alias}</option> </volist> </volist> </volist> </select>