Yii::app()->User->Checkaccess('controller.action') Is Not Workig

hi all,

iam using Yii-Rights and i want to hide all links on a page depending on authority of user on this links.

for example :

array('label'=>'Assign Tasks', 'url'=>array('/AssignedTask/admin'),'visible'=> Yii::app()->user->checkAccess('AssignedTask.Admin')

but its not working.

tell me how to fix it.

thanks in advance.