求ctreeview中url的具体使用方法 [ 新手入门 ]

这个是controller里的代码：

public function actionInfoClass()
{
  $this->render('infoClass');
}
public function actionAjaxClassTree()
{
  if (!Yii::app()->request->isAjaxRequest) {
    exit();
  }
  $parentId = 'null';
  if (isset($_GET['root'])) {
    $parentId = (int) $_GET['root'];
  }
  $req = Yii::app()->db->createCommand(
    "SELECT m1.infoClass_id, m1.infoClass_name AS text, m2.infoClass_id IS NOT NULL AS hasChildren "
            . "FROM infoClass_list AS m1 LEFT JOIN infoClass_list AS m2 ON m1.infoClass_id=m2.infoClass_fid "
            . "WHERE m1.infoClass_fid <=> $parentId "
            . "GROUP BY m1.infoClass_id ORDER BY m1.infoClass_name ASC"
  );
  $children = $req->queryAll();
  echo str_replace(
    '"hasChildren":"0"',
    '"hasChildren":false',
    CTreeView::saveDataAsJson($children)
  );
  exit();
}

这是view中的代码：

$this->widget(
  'CTreeView',
  array('persist'=>'cookie',
    'animated'=>'fast',
    'url' => array('ajaxClassTree'),
    'htmlOptions'=>array('id'=>'treeview','class'=>'treeview treeview-famfamfam'))
);

我每次点击展开的都是第一级的分类，应该怎么样才能点击展开指定的子类，求详细指导。。。:(