$dp_id = $this->getParam('dpId');

if(!empty($this->getParam('dpId'))) { 
    $this->smarty->assign('developer', get_developers($this->getParam('dpId'))); 
}

以上PHP会报错:  Can't use method return value in write context

解决办法为分开写

$dp_id = $this->getParam('dpId');

if(!empty($dp_id)) {

	$this->smarty->assign('developer', get_developers($this->getParam('dpId')));

}