Prado\Web\UI\WebControls\TRequiredFieldValidator::validateRadioButtonGroup PHP Method

    private function validateRadioButtonGroup($control)
    {
        $initial = trim($this->getInitialValue());
        foreach ($control->getRadioButtonsInGroup() as $radio) {
            if ($radio->getChecked()) {
                if (strlen($value = $radio->getValue()) > 0) {
                    return $value !== $initial;
                } else {
                    return true;
                }
            }
        }
        return false;
    }