无限级 SelectTree 类

[php]
/*
author:  nick
date: 2009.05.17
功能：生成SeletTree
属性:
      $result               结果集
      $id_field             自身id字段
      $parent_field         父类id字段
      $option_text            选项显示名称
      $select_name            下拉菜单的名称
      $elected                默认选中
      $no_top                是否需要顶层选项
      $level                层深度
      $parent_id            同层中的id
*/
class SelectTree{
    public $result;
    public $select_name;
    public $option_text;
    public $elected;
    public $id_field;
    public $parent_field;
    public $no_top;
    public $level;
    public $parent_id;
    public $getarray;
    
    function __construct($result,$id_field,$parent_field,$option_text,$select_name='',$elected=0,$no_top=0,$level=0,$parent_id=0){
        $this->result       =$result;
        $this->id_field     =$id_field;
        $this->parent_field =$parent_field;
        $this->option_text  =$option_text;
        $this->select_name  =$select_name;
        $this->elected      =$elected;
        $this->no_top       =$no_top;
        $this->level        =$level;
        $this->parent_id    =$parent_id;
        $this->getarray     =self::getArray();
    }
    
/*
功能：返回Tree二维数组
*/
    function getArray(){
        $arrays=array();
        while($row=mysql_fetch_array($this->result)){
            $arrays[$row[$this->parent_field]][$row[$this->id_field]]=$row;
        }
        return $arrays;
    }
/*
功能：获取SelectTree
*/
    function getSelectTree(){
     $tree = '<select name="'.$this->select_name.'">';
     if($no_top){
      $tree .= '<option value="0">最顶层</option>';
     }
     self::buildTree($this->getarray,&$tree,$this->id_field,$this->option_text,$this->selected,$this->level,$this->parent_id);  //生成树状结构
     $tree .= '</select>';
     return $tree;
    }
    

/*
功能：递归构建树状结构
*/
function buildTree($array,&$tree,$option_value,$option_text,$selected,$level=0,$parent_id=0){
     if(is_array($array[$parent_id])){
      for($i=0;$i<$level;$i++)
       $space .= '   ';     //选项缩进深度
    
          foreach($array[$parent_id] as $key => $value){
               if($value[$option_value] == $selected){
                $tree .= '<option value="'.$value[$option_value].'" selected="selected">'.$space.$value[$option_text]."</option>";
               }else{
                $tree .= '<option value="'.$value[$option_value].'">'.$space.$value[$option_text]."</option>";
               }
               $tree .=self::buildTree($array,&$tree,$option_value,$option_text,$selected,$level+1,$key);
          }
     }else{
      $tree .= '';
     }
}

}

/****************************************************************************/
header("CONTENT-TYPE:TEXT/HTML;CHARSET=UTF-8");
mysql_connect("localhost","root","root");
mysql_select_db("tree");
mysql_query('set names utf8');
$result = mysql_query("select * from tvmenu");

$tree=new SelectTree($result,'id','bid','name','tree');
echo $tree->getSelectTree();

[/php]