How to programmatically assign the main section to the infoblock elements without resetting all the others?

Question

1C-Bitrix

On the site, the goods belong to several categories at the same time, and the task was to specify the root category as the main section. Tried through update (), specifying the desired section in the "IBLOCK_SECTION_ID" parameter, does not work, only the selected section remains, the rest of the bindings are reset. Has anyone faced such a task? How did they decide?

Answer 1

If you look at the Add and Update methods of the CIblockElement class, the update is performed by the following code:

if(array_key_exists("IBLOCK_SECTION_ID", $arFields))
{
    if (!array_key_exists("IBLOCK_SECTION", $arFields))
    {
        $arFields["IBLOCK_SECTION"] = array($arFields["IBLOCK_SECTION_ID"]);
    }
    elseif (is_array($arFields["IBLOCK_SECTION"]) && !in_array($arFields["IBLOCK_SECTION_ID"], $arFields["IBLOCK_SECTION"]))
    {
        unset($arFields["IBLOCK_SECTION_ID"]);
    }
}

Thus, if you pass IBLOCK_SECTION_ID and do not pass an array of other sections - IBLOCK_SECTION, then they will be reset to zero.