public function init()
{
if ($this->showAttrName === null || $this->pkAttrName === null || $this->parentAttrName === null) {
throw new InvalidParamException('树形结构组件缺失必要属性！');
}
parent::init();
$this->itemsHandle();
}
/**
* @inheritdoc
*/
public function renderHtml()
{
$this->registerAsset();
return parent::renderHtml();
}