Change the city to dropdown in Edit Order Billing Address admin

Question

I want to change the city to dropdown in Edit Order Billing Address admin.

1. I try to update table eav_attribute in database. I changed frontend_input='select'; and copy the source model of country customer/entity_address_attribute_source_country. It change my textbox to dropdown but when I tried to duplicate the code of country in below path.

app\code\core\Mage\Customer\Model\Resource\Address\Attribute\Source\Country.php app\code\core\Mage\Customer\Model\Entity\Address\Attribute\Source\Country.php

and create a file app\code\core\Mage\Customer\Model\Resource\Address\Attribute\Source\City.php app\code\core\Mage\Customer\Model\Entity\Address\Attribute\Source\City.php

just replace the Country to City in the code and update again the table and change the value customer/entity_address_attribute_source_city. I already encountered error.

2. I already found the form in app\design\adminhtml\default\default\template\sales\order\address\form.phtml but the code is hard to change because it is just a single line.. see below.

getForm()->toHtml() ?>

Anyone can help me on this requirements.

Answer 1

I already find a way by replacing it with jquery.

<script  type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script>
<script>jQuery.noConflict()</script>
<script>
  jQuery(document).ready(function($) {
        var value = $("#city").val();
        //alert(value);
        $('#city').replaceWith( $('<select id="cities" name="city"><option value="Abha">Abha</option><option value="Al Qunfudhah">Al Qunfudhah</option></select>') );
        $('select option[value="'+value+'"]').attr("selected",true);
        e.preventDefault();

  });
</script>