add carrier field dropdown field in order grid magento

Question

i am adding the form field through the observer but cannot able to post form field on mass action below my code

public function render(Varien_Object $row)
{

    $orderdata=Mage::getModel('sales/order')->load($row->getEntityId());

        $value .='Carrier:';
        $value .='<select name="carrier'.$row->getEntityId().'">';
        $options=$this->getCarrierOption();
        foreach ($options as $option) {
            $value .='<option value="'.$option['value'].'">'.$option['label'].'</option>';
        }
        $value .='</select>';
    return $value.$valyee;
    }
}  

any help will be appreciated.

Answer 1

This approach is wrong, you cannot post from the grid area because there is no form in grid area for posting the form fields, form fields must be in between tags.

Try something like this.

<form method="post" id="sales_order_grid_massaction-form" action="">
    <select class="required-entry select absolute-advice local-validation" id="sales_order_grid_massaction-select">
<option value="order">Order</option>
</select>
</form>

you can see in my code all fields are come under form tag so you should do like this.

Answer 2

rather than using an Observer why don't you create a module. You could override the collection class and display the carrier type for each order and mass actions will work. You could try with the references from the following sites to help you out
https://inchoo.net/magento/how-to-extend-magento-order-grid/

http://www.demacmedia.com/magento-commerce/mini-tutorial-adding-column-to-orders-grid-in-magento-backend/

hope that helps!