Prado\Web\UI\TPage::getPostBackEventParameter PHP Метод

    public function getPostBackEventParameter()
    {
        if ($this->_postBackEventParameter === null && $this->_postData !== null) {
            if (($this->_postBackEventParameter = $this->_postData->itemAt(self::FIELD_POSTBACK_PARAMETER)) === null) {
                $this->_postBackEventParameter = '';
            }
        }
        return $this->_postBackEventParameter;
    }