EntityDataProvider::fetchData

protected function fetchData()
{
	if($this->data === null)
	{
		$this->data = [];
		/** @var BitrixMainEntityDataManager $className */
		$className = $this->getTableClass();
		if(!is_a($className, DataManager::class, true) || is_object($this->source))
		{
			return;
		}
		try
		{
			$data = $className::getByPrimary($this->source, $this->getGetListParameters())->fetch();
		}
		catch(SystemException $systemException)
		{
			$data = $className::getByPrimary($this->source, ['select' => ['*']])->fetch();
		}
		if($data)
		{
			$this->data = $data;
		}
	}
}