Not able to assign value to hidden form field using form_alter hook

Question

I have a form in which field my_consultant_id is "Hidden integer" type field and having widget type as "Hidden field".

I am assigning the value to this field by using hook_form_alter

function threebl_summary_report_form_alter(&$form, &$form_state, $form_id) {
    if($form_id == 'eck__entity__form_add_summary_report_comparative_client_gro‌​up') {
        global $user; 
        $form['field_created_by']['und'][0]['#default_value'] = (int) $user->uid;
    }
}

But not able to set the value for that field.

If I inspect the form it shows html code for field like:

<div class="field-type-field-hidden-integer field-name-field-my-consultant-id field-widget-field-hidden form-wrapper" id="edit-field-my-consultant-id">

Thanks in advance.

Answer 1

I managed to do it by validate handler of the form. Using validate handler I assigned my value to the form variable before submit.

In form alter hook call validate handler like below

$form['#validate'][] = 'my_module_name_form_validate';

And following is the validate handler function code

function my_module_name_form_validate(&$form, &$form_state) {    
$form['field_my_field']['#parents'] = array('field_my_field');
form_set_value($form['field_my_field'],array('und' => array(0 => array('value' => $new_value))),$form_state);

}

For reference please go through link

Answer 2

I think you are missing default value.

try

$form["my_consultant_id"][LANGUAGE_NONE][0]['value']['#default_value'] = (int)$user->uid;