我在控制器的索引操作中有这些代码:
public function actionIndex()
{ 
  $cid = @$_GET['cid'];
  $country = Country::model()->findByPk($cid);
  if($cid)
    $dataProvider=new CActiveDataProvider('City', array(
      'criteria'=>array(
        'condition'=>'ci_co_id ='.$cid,
      ),
    ));
  else
     $dataProvider=new CActiveDataProvider('City'); 
  $this->render('index',array(
 'dataProvider'=>$dataProvider,
     'country' => $country
    ));
  }
这些在 view/index.php 文件中:
<?php 
$this->widget('zii.widgets.grid.CGridView', array(
  'id'=>'city-grid',
  'dataProvider'=>$dataProvider,
  'filter' => $dataProvider,
  'columns'=>array(
    array(
        'name' => ' ',
        'value' => '$row + 1',
    ),  
    'ci_name',
    'ci_pcode',
    array(
        'class'=>'CButtonColumn',
    ),
   )
));
?>
但是 Yii 给了我这个错误:
CActiveDataProvider and its behaviors do not have a method or closure named "getValidators". 
问题是什么?