Why doesn't CIBlockElement::getList return IBLOCK_SECTION?

Question

1C-Bitrix

I make a request to the API to get the elements of the infoblock (well, in this particular example).

\Bitrix\Main\Loader::includeModule("iblock");
$rItems = \CIBlockElement::getList(array("SORT" => "ASC"),
    array(
        'ID' => intval($elId),
        'IBLOCK_ID' => intval($iblockId),
    ));
print_r($rItems->Fetch());

I expect to see in the array:
IBLOCK_SECTION_ID where the main section will be shown (it comes)
and IBLOCK_SECTION where the array is the ID of the sections to which the element is tied. But this array does not exist.

Why is this array not coming?

In what cases does this IBLOCK_SECTION field come at all ? Indeed, in the documentation it is https://dev.1c-bitrix.ru/api_help/iblock/fields.ph... I thought that this was due to the flag (Allow selection of the main section for binding.) in the infoblock settings, but trying a similar selecting another infoblock for an element that does not have this option, I get a similar result.

How to get a list of all sections to which this element is tied?

Answer 1

Why is this array not coming?

As I understood from what I saw in the CIBlockElement class itself, the IBLOCK_SECTION field and should not come to getList, there is no logic for its formation. It is only in the Update of this class and serves to be able to link an element to several sections + specify the Main section IBLOCK_SECTION_ID

In what cases does this IBLOCK_SECTION field come at all? It's in the documentation...

It seems to never be given to the API. Serves only for the needs of CIBlockElement::Update

How to get a list of all sections to which this element is tied?

Well, here you have to use CIBlockElement:: GetElementGroups