In Yii implementiertes Dropdown-Menü für mehrstufige Verknüpfungen

<?php echo CHtml::activeDropDownList($model,&#39;zmg_id&#39;,MemGroup::model()->getMemGroup(),array(
    &#39;class&#39;=>&#39;s_ipt w_120&#39;,
    &#39;empty&#39;=>&#39;请选择会员组&#39;,
    &#39;ajax&#39; =>array(
          &#39;type&#39;=>&#39;GET&#39;,
          &#39;url&#39;=>CController::createUrl(&#39;cmpTemplates/getMemType&#39;),
          &#39;update&#39;=>&#39;#CmpTemplates_zmg_ids&#39;,
          &#39;data&#39;=>array(&#39;mid&#39;=>"js:this.value")
          ),
    ))?>
<?php echo $form->dropDownList($model,&#39;zmg_ids&#39;,array(),array(&#39;class&#39;=>&#39;s_ipt w_120&#39;,&#39;empty&#39;=>&#39;选择会员等级&#39;))?>

/**
 * 获取会员组,对应的会员等级，用于下拉菜单
 */
public function actionGetMemType($mid=0)
{
  $criteria=new CDbCriteria;
  $criteria->compare('zmg_id',$mid);
  $memType = MemType::model()->findAll($criteria);
  $name = '选择会员等级';
  echo CHtml::tag('option', array('value'=>0), $name, true);
  foreach($memType as $val) {
    echo CHtml::tag('option', array('value'=>$val->zmt_id),CHtml::encode($val->zmt_title),true);
  }
}

/*
* 取会员组信息
*/
public function getMemGroup($type=null){
  if($type==null){
    $criteria=new CDbCriteria;
    $criteria->compare('type','1');
    $memGroup = MemGroup::model()->findAll($criteria);
    return CHtml::listData($memGroup,'zmg_id','zmg_title');
  }else{
    $level = $this->getMemGroup();
    if(array_key_exists($type,$level)){
      return $level[$type];
    }
  }
}