public function HasField ($fieldOrFieldName = NULL) {
		$fieldName = NULL;
		if ($fieldOrFieldName instanceof \MvcCore\Ext\Forms\IField) {
			$fieldName = $fieldOrFieldName->GetName();
		} else if (is_string($fieldOrFieldName)) {
			$fieldName = $fieldOrFieldName;
		}
		return isset($this->fields[$fieldName]);
	}