How to set a list(enum) type property of an infoblock using api methods in bitrix?

Question

1C-Bitrix

Internet shop on Bitrix. There are goods and trade offers.
The trade offers infoblock has the "Size" property, code "SIZE". This property is a list (not plural).
How to change the property value using API methods (or set if not already set)?
A separate sub-question: Let's say I
have already created SIZE property list elements, for example, the following 4: "100*100","100*150","150*150","150*200"
suppose with code 100 to set the value of the property SIZE "300*400" which is not yet in the list. What is the best way to do this?

Answer 1

As a result, I wrote a function that takes 3 parameters: 1) the value that the list property should have, 2) the ID of the infoblock, 3) the property code - the function returns the ID of the existing property, and if it does not find it, it creates a record in the property and returns its ID. False is returned on error
Function code and usage examples here blog.ivru.net/?id=175
Directly on the question asked, the creation of goods or sales offers with a property binding of the list (enum) type is carried out as follows:

$el = new CIBlockElement;

$arLoadProductArray = array(
  "IBLOCK_ID"=>2, // IBLOCK торговых предложений
  "NAME"=>"Имя торгового предложения",
  "ACTIVE"=>"Y",
  "PROPERTY_VALUES"=>array(
    "CML2_LINK"=>$PRODUCT_ID, // Свойство типа "Привязка к товарам (SKU)", связываем торг. предложение с товаром
    "CML2_ARTICLE"=>"Артикул торгового предложения",
    "SIZE"=>$sizePropId,
    "CLOTH"=>$clothPropId
  )
);

$product_offer_id = $el->Add($arLoadProductArray);

In the code above, I have the SIZE and CLOTH properties of the list (enum) type in the $sizePropId and $clothPropId variables, the identifiers of the required property values ​​are passed.
To get the identifier by value, I provided a link to the corresponding function.

Answer 2

1) Update list property
CIBlockPropertyEnum::GetList - get list property value ID
CIBlockElement::SetPropertyValues ​​- update element property using list property value ID
If list property value ID is empty, then:

$ibpenum = new CIBlockPropertyEnum;
if($PropID = $ibpenum->Add() 
{CIBlockElement::SetPropertyValues

More details here https://dev.1c-bitrix.ru/api_help/iblock/classes/c...