Auto populate custom field after selecting related field from list

Hi,
I’m trying to populate custom field after selecting related field from the list in cases module. However, it’s not working. I’ve done exactly same as suggested in other posts but still it’s not working. Below is the code:

       0 =>
             array(
                    'name' => 'contact_c',
                    'studio' => 'visible',
                    'label' => 'LBL_CONTACT',
                    'displayParams' =>
                    array(
                        'field_to_name_array' => array(
                            'id' => 'contact_id_c', //Check the case vardef cache for the exact id field
                            'name' => 'contact_c', //Check the case vardef cache for the exact name field
                            'phone_work' => 'contact_phone_work_c' // contact field => case field to populate
                        ),
                    ),
                ),
            ),

Please advise if any other step is required for this to work.

Thanks.

@umesh.m
Change some code:

 array(
         'name' => 'contact_c',
         'studio' => 'visible',
         'label' => 'LBL_CONTACT',
         'displayParams' =>
                array(
                      'phone_work' => 'contact_phone_work_c' // contact field => case field to populate
                ),
        ),

The parameter ‘field_to_name_array’ used in difficult decision. You can look at the file: modules/Employees/metadata/editviewdefs.php as example about the parameter:
the filed ‘reports_to_name’ and the parameter ‘customCode’.