问将用户登录到magento中的后端管理订单

EN

<events>
    <sales_order_place_after>
        <observers>
            <orderenteredby>
                <type>singleton</type>
                <class>orderenteredby/observer</class>
                <method>implementOrderMethod</method>
            </orderenteredby>
        </observers>
    </sales_order_place_after>

class MagePal_OrderEnteredBy_Model_Observer 
{

    public function implementOrderMethod($event)
    {
        $_order = $event->getOrder();

        if($this->_isAdmin()){
            $_user = Mage::getSingleton('admin/session');
            $firstname = $_user->getUser()->getFirstname();
            $lastname = $_user->getUser()->getLastname();
            $enterBy = "Order entered by {$firstname} {$lastname}";  
        }
        else{
            $enterBy = 'Ordered Online';
        }
        $_order->addStatusHistoryComment($enterBy)
               ->setIsVisibleOnFront(false)
               ->setIsCustomerNotified(false);

        return $this;
    }

    protected function _isAdmin(){
        if(Mage::app()->getStore()->isAdmin()){
            return true;
        }

        if(Mage::getDesign()->getArea() == 'adminhtml'){
            return true;
        }

        return false;
    }
}