Bitrix. How to apply the function only to the product being added to the cart?

Question

1C-Bitrix

Good afternoon.
I change the price of the product when adding to the cart to my own.
In init.php, this code changes the item price to 2000 for all items in the cart.
How to change the price for only one added product?

class CCatalogProductProviderCustom extends CCatalogProductProvider {

      public static function GetProductData($arParams) {


        $arResult = parent::GetProductData($arParams);

        $i++;

        $arResult = [
          'BASE_PRICE' => '2000', // ПРИМЕНЯЕТСЯ КО ВСЕМ ТОВАРАМ В КОРЗИНЕ
        ]
        +
        $arResult;


        return $arResult;
      }
    }


    addEventHandler(
      'sale',
      'OnSaleBasketItemRefreshData',
      'BeforeBasketAddHandler'
    );


    function BeforeBasketAddHandler($BasketItem) {

      $BasketItem->setField(
        "PRODUCT_PROVIDER_CLASS",
        "CCatalogProductProviderCustom"
      );
    }

Answer 1

I can offer several options for testing:
1) instead of setField, try setFieldNoDemand
2) after setField $basketItem->save();
3) the BasketItem class object has a setPrice method