ZF2 (2.1 method) Populating select/drop down element in form - select

Question

I used Zend Framework 2.1(not 2.0x) method to populate a select/drop down that is described in following links:
http://zf2.readthedocs.org/en/develop/modules/zend.form.advanced-use-of-forms.html#handling-dependencies
http://www.michaelgallego.fr/blog/2012/11/09/discover-whats-coming-for-zendform-in-zf-2-1/
Though it seems I have done as they told I got a error message like:
*... ::__construct() must be an instance of Zend\Db\TableGateway\TableGateway, none given, called in ...*
which seems service locator is not used properly.
My form code that adds my FieldSet SupplierFieldset:
namespace Inventory\Form;
use Zend\Form\Form;
use Inventory\Model;
class ItemForm extends Form
{
public function init()
{
$this->add(array(
'name' => 'sup_code',
'type' => 'Inventory\Form\SupplierFieldset'
));
}
}
My 'SupplierFieldset' class:
namespace Inventory\Form;
use Inventory\Model;
use Zend\Form\Element;
use Zend\Form\Fieldset;
use Zend\ServiceManager\ServiceLocatorAwareInterface;
use Zend\ServiceManager\ServiceLocatorInterface;
use Zend\InputFilter\InputFilterProviderInterface;
use Inventory\Model\SupplierTable;
use Inventory\Model\Supplier;
class SupplierFieldset extends Fieldset implements ServiceLocatorAwareInterface
{
protected $serviceLocator;
protected $supplierTable;
public function init()
{
parent::__construct('Suppliers Code');
$this->setLabel('Supplier Code');
$this->setName('supplier_code');
$suppliers = $this->getSupplierTable()->fetchAll();
$select = new Element\Select('supplier_code');
$options = array();
foreach ($suppliers as $supplier) {
$options[$supplier->id] = $supplier->sup_code;
}
$select->setValueOptions($options);
}
public function setServiceLocator(ServiceLocatorInterface $serviceLocator)
{
$this->serviceLocator = $serviceLocator;
}
public function getServiceLocator()
{
return $this->serviceLocator;
}
public function getSupplierTable()
{
if (!$this->supplierTable) {
$sm = $this->getServiceLocator();
$this->supplierTable = $sm->get('Inventory\Model\SupplierTable');
}
return $this->supplierTable;
}
}
My Module.php getFormElementConfig() function:
public function getFormElementConfig()
{
return array(
'factories' => array(
'SupplierFieldset' => function($sm) {
$serviceLocator = $sm->getServiceLocator();
$supplierTable = $serviceLocator->get('Inventory\Model\SupplierTable');
$fieldset = new SupplierFieldset($supplierTable);
return $fieldset;
}
)
);
}
My SupplierTable.php model:
namespace Inventory\Model;
use Zend\Db\TableGateway\TableGateway;
class SupplierTable
{
protected $tableGateway;
public function __construct(TableGateway $tableGateway)
{
$this->tableGateway = $tableGateway;
}
public function fetchAll()
{
$resultSet = $this->tableGateway->select();
return $resultSet;
}
}
I know SupplierTable model's constructor needs a TableGateway $tableGateway parameter. But this model is working properly when called from SupplierController.