The complete form structure. #process, #after_build, #element_validate, and other handlers being invoked on a form element may use this reference

Stores the gathered validation handlers. This property is uncacheable. Type:

The form element that triggered submission, which may or may not be a button (in the case of Ajax forms). This key is often used to distinguish between various buttons in a

public FormState::setTriggeringElement($triggering_element)

public FormState::getFormObject() Returns

public FormState::isMethodType($method_type) Returns

public FormState::setValidateHandlers(array $validate_handlers)

public FormState::isRebuilding() Determines

Stores information about the state of a form. Hierarchy class \Drupal\Core\Form\

public FormState::getBuildInfo() Returns