Changes submitted form values during form validation.
Use this function to change the submitted value of a form element in a form validation function, so that the changed value persists in $form_state through to the submission handlers.
Note that form validation functions are specified in the '#validate' component of the form array (the value of $form['#validate'] is an array of validation function names). If the form does not originate in your module, you can implement hook_form_FORM_ID_alter() to add a validation function to $form['#validate'].
array $element: The form element that should have its value updated; in most cases you can just pass in the element from the $form array, although the only component that is actually used is '#parents'. If constructing yourself, set $element['#parents'] to be an array giving the path through the form array's keys to the element whose value you want to update. For instance, if you want to update the value of $form['elem1']['elem2'], which should be stored in $form_state->getValue(array('elem1', 'elem2')), you would set $element['#parents'] = array('elem1','elem2').
mixed $value: The new value for the form element.
lib/ Drupal/ Core/ Form/ FormStateInterface.php, line 398
- Provides an interface for an object containing the current state of a form.
public function setValueForElement(array $element, $value);