DropDown for pageSize in CGridView

I found myself in the need for a dropDownList to select the page size on a CGridView. I was amazed that only a few lines of code where required. So i thought i'd share.

On top of my controller action for the gridview (if you used CRUD, this is actionAdmin() ) i added:

// page size drop down changed
if (isset($_GET['pageSize'])) {
    Yii::app()->user->setState('pageSize',(int)$_GET['pageSize']);
    unset($_GET['pageSize']);  // would interfere with pager and repetitive page size change
}

In the model (e.g. model/User.php) the data provider in search() is configured like:

return new CActiveDataProvider(get_class($this),array(
    'pagination'=>array(
        'pageSize'=> Yii::app()->user->getState('pageSize',Yii::app()->params['defaultPageSize']),
    ),
    'criteria'=>$criteria,
));

And finally the view (e.g. views/user/admin.php) :

<?php 
// put this somewhere on top
$pageSize=Yii::app()->user->getState('pageSize',Yii::app()->params['defaultPageSize']); ?>

<?php
// we use header of button column for the drop down
// so change the CButtonColumn in columns array like this:
...
array(
    'class'=>'CButtonColumn',
    'header'=>CHtml::dropDownList('pageSize',$pageSize,array(20=>20,50=>50,100=>100),array(
        // change 'user-grid' to the actual id of your grid!!
        'onchange'=>"$.fn.yiiGridView.update('user-grid',{ data:{pageSize: $(this).val() }})",
    )),
),

Et voilà, we have a page size selector that keeps it's value in user state.


EDIT:
Forgot to mention the configuration in the application parameters:

// Accessable with Yii::app()->params['paramName']
'params'=>array (

    'defaultPageSize'=>20,

EDIT2:
Changed to match the CRUD generated code.