public function actionIndex() {
  $dataPRovider = new CActiveDataProvider('User'); // The dataprovider your grid uses
  if (!$this->isAjaxRequest()) {
    $dataProvider->crITeria->addCondition('1 = 0'); // You Could also use 0,but I think this is more clear
  }

  [...]
}

然后在javascript部分的视图中：

$(function() { // If you are using jquery this is executed when the page is loaded
  $.fn.yiiGridView.update("{id-of-your-grid-view}");
});