add query parameter to render

i need to add some parameter to view url .

for example add cat=all parameter to following view url :

localhost/sell/frontend/web/index.php?r=product/index

and this is my index action :

how should i do that?

$this->render(‘index’,array(

		'dataProvider'=>$dataProvider,


		'cat' => 'all',


	));

Here cat parameter will not be seen in url but you can retrieve it in the index page.