/**
* Add a plain text error message to a field on this form. It will be saved into the session
* and used the next time this form is displayed.
* @param string $fieldName
* @param string $message
* @param string $messageType
* @param bool $escapeHtml
*/
public function addErrorMessage($fieldName, $message, $messageType, $escapeHtml = true)
{
Session::add_to_array("FormInfo.{$this->FormName()}.errors", array('fieldName' => $fieldName, 'message' => $escapeHtml ? Convert::raw2xml($message) : $message, 'messageType' => $messageType));
}
