How to get triggering_element

Question

I want to get triggering_element element on form_alter after form rebuild, Also I know that this could be used on submit handler on Ajax controller to findout which element cause form submit or Ajax triggered.

So how can I get triggering_element after Ajax call or form submissions?

Answer 1

Eyal is correct. FormState has a method getTriggeringElement. See the original change record for details.

$form_state->getTriggeringElement();

and if you want to get id try

$triggerdElement = $form_state->getTriggeringElement();
$htmlIdofTriggeredElement = $triggerdElement['#id'];

Answer 2

My preferred method is:

$triggering_element = $form_state->getTriggeringElement();
$button_name = $triggering_element['#name'];
if ($button_name === 'button1') {
  // ...
}

Works both for validateForm() and submitForm().

Ensure you have #name for all your buttons. E.g.:

$form['button1'] = [
  '#type' => 'submit',
  '#name' => 'button1',
  '#value' => $this->t('Button 1'),
];

Compared to $triggering_element['#id'] it's more stable because #id auto-generated and can change implicitly.

Compared to $triggering_element['#value'] it's better because:
- #value can be not unique;
- #value is a part UI (button label) and frequently changes.

Answer 3

3

$triggering_element = $form_state->getTriggeringElement();
$button_name = $triggering_element['#name'];
if ($button_name === 'button1') {
  // ...
}

Works both for validateForm() and submitForm().

Ensure you have #name for all your buttons. E.g.:

$form['button1'] = [
  '#type' => 'submit',
  '#name' => 'button1',
  '#value' => $this->t('Button 1'),
];

This is the correct answer.

Answer 4

Using jQuery you can get the element using ajaxComplete function

$( document ).on( "ajaxComplete", function( event, request, settings ) {
    if(settings.extraData != undefined) {
    console.log(settings.extraData._triggering_element_name);
    }
});