Problem With Dependable Dropdown In Update Page

Yii 1.1 General Discussion
1

I have used dependable drop down


<?php //echo $form->dropDownList($model,'country', CHtml::listData(Country::model()->findAll(), 'country_name', 'country_name'), array('empty'=>'Select Country'));

				echo  $form->dropDownList($model,'country',CHtml::listData(Country::model()->findAll(), 'country_name', 'country_name'),

				array(

				'ajax' => array(

				'type'=>'POST', 

				'url'=>CController::createUrl('State/Dropupdate1'), //url to call.

				'update'=>'#city_id123',

				),'empty'=>'Select Country')); 

	

echo $form->dropDownList($model,'state',array(), array('empty'=>'Select State','id'=>'city_id123')); 

		?>

This is working fine, on create page

But when we update this page the "State" is not selected in default,

How this is possible?