1.在catalog类里面：

	/**
	 * 级联显示
	 * 分类目录递归列表
	 * 返回父类的所有子类
	 * &$categoryList 引用传值返回
	 */
       const SHOW_SELECT='————请选择————';


	public function showAllCategory(&$categoryList,$category,$parentid=0,$separate="")
	{
		foreach($category as $k=>$v){
			if($v['parentid']==$parentid){
				$v['title']=$separate.$v['title'];
				$categoryList[]=$v;
				$this->showAllCategory($categoryList,$category,$v['id'],$separate."——");
			}
		}
	}
/**
* 分类目录下拉列表
*/ 
public function showAllSelectCategory($module,$selectText='')
{
$category=Category::model()->select('id,title,parentid')->order('sort desc')->findAll("module=$module");
$categoryList=array();
$this->showAllCategory($categoryList,$category);
if(!empty($selectText))
$categorys=array('0'=>$selectText);
else 
$categorys=array(''=>Category::SHOW_SELECT);
foreach($categoryList as $v){
$categorys[$v[id]]=$v[title];
}
return $categorys;
}

		$this->render('create',array(
			'model'=>$model,
			'categorys'=>Category::model()->showAllSelectCategory(Yii::app()->params['module']['article']),
		));

	<div class="row">
		<?php echo $form->labelEx($model,'cid'); ?>
		<?php echo $form->dropDownList($model,'cid',$categorys); ?>
	</div>

    	if(!empty($_GET['cid'])){
    		$categoryList=array();
    		$categoryList[]=$_GET['cid'];
			Category::model()->getAllCategoryIds($categoryList,Category::model()->findAll('module='.Yii::app()->params['module']['article']),$_GET['cid']);
		    $criteria->addInCondition('cid',$categoryList);
    	}
    	if(!empty($_GET['title']))
    		$criteria->addSearchCondition('title',$_GET['title']);
		$dataProvider=new CActiveDataProvider('Article',array(
			'criteria'=>$criteria,
			'pagination'=>array(
        		'pageSize'=>Yii::app()->params['girdpagesize'],
    		),	
		));

public function getAllCategoryIds(&$categoryList,$category,$parentid=0){
			foreach($category as $k=>$v){
			if($v['parentid']==$parentid){
				$categoryList[]=$v['id'];
				$this->getAllCategoryIds($categoryList,$category,$v['id']);
			}
		}
	}