protected function handlePostBackEvent()
{
$sender = $this->getPostBackTarget();
if (is_null($sender)) {
if (!is_null($this->masterPage)) {
$this->masterPage->handlePostBackEvent();
}
} else {
if ($sender->hasProperty('CausesValidation') && $sender->CausesValidation) {
$this->validate();
}
if ($sender instanceof IPostBackEventHandler) {
$sender->raisePostBackEvent($this->getPostBackParameter());
}
}
}