在单击提交按钮时传递日期选择器值给控制器

我有一个sql查询，我想用DatePicker传递日期。我做了参数绑定，如果我直接给绑定的变量赋值，它就能工作。我不知道如何准确地通过点击提交按钮后的值。在我看来，我使用TbActiveForm和日期选择器小部件。视图文件link。php是这样的:

<?php
$form = $this->beginWidget(
    'bootstrap.widgets.TbActiveForm',array(
    'id' => 'inlineForm',
    'type' => 'inline',
    'htmlOptions' => array('class' => 'well'),
));
?>
Start Date
<?php $this->widget('bootstrap.widgets.TbDatePicker',array(
                 'name' => 'from_date',
                 'options' => array('format' => 'yyyy-mm-dd')
)); 
?>
End Date           
<?php $this->widget('bootstrap.widgets.TbDatePicker',array(
                'name' => 'to_date',
                'options' => array('format' => 'yyyy-mm-dd')
  ));
?>
&nbsp;
<!-- Submit Button -->   
<?php $this->widget('bootstrap.widgets.TbButton',array(
                'buttonType' => 'Submit',
                'label' => 'Submit',
                 'type' => 'primary',
                 'url' => 'Link'  
 )); 
  $this->endWidget();

在控制器中，我有:from_date和:to_date分别绑定到变量$from和$to。如果我为变量提供值，查询工作正常，因此绑定没有问题。控制器代码如下所示:

  public function actionLink()
      {
    // $from = $_GET['from_date'];
    // $to = $_POST['to_date'];
$from=!empty($_POST['from_date'])?$_POST['from_date']:'2014-01-01';
    $to=!empty($_POST['to_date'])?$_POST['to_date']:'2014-02-01';
 $sql = "SELECT [Ordernumber]
  ,[Order_Date]
  FROM [Orders]
  WHERE CAST(Order_Date As Date) BETWEEN :from_date AND :to_date
  ORDER BY Order_Date ";
 $sql2 = "SELECT COUNT(*)
        FROM [Orders]
        WHERE CAST(Order_Date As Date) BETWEEN :from_date AND :to_date";
         $connection=Yii::app()->db;
         $command=$connection->createCommand($sql2); 
       //   $command = $connection->createCommand('SELECT COUNT(*) FROM (' . $sql . ') as count_alias');
          $command->bindParam(':from_date',$from,PDO::PARAM_STR);
          $command->bindParam(':to_date',$to,PDO::PARAM_STR);
          $dataProvider = new CSqlDataProvider($sql, array('keyField' => 'Order_Date',
            'params' => array(
                ':from_date' => $from,
                 ':to_date' => $to),
            'totalItemCount' => $command->queryScalar(),
            'pagination' => array(
                'pageSize' => 20)));

    // renders the view file 'protected/views/site/index.php'
    // using the default layout 'protected/views/layouts/main.php'
      $this->render('link',  array('dataProvider' => $dataProvider));
}

所以如果我使用:

 $from = $_POST['from_date'];
 $to = $_POST['to_date'];

我得到一个错误:undefined index from_date.

我想知道我必须为Submit按钮编写什么代码，以便它将DatePicker的值传递回控制器。以及控制器如何读取值

现在如果我点击提交按钮它会重新加载页面但是通过

    $from=!empty($_POST['from_date'])?$_POST['from_date']:'2014-01-01';
    $to=!empty($_POST['to_date'])?$_POST['to_date']:'2014-02-01';