How to get associated(child) product id, name and other details using configurable product id in Magento 2

Question

I need to get all the child products details like id, name, color from a configurable product id in a custom phtml page.

    $objectManager = \Magento\Framework\App\ObjectManager::getInstance();

    $product = $objectManager->get('Magento\Framework\Registry')->registry('current_product');//get current product

    $productTypeInstance = $product->getTypeInstance();

    $usedProducts = $productTypeInstance->getUsedProducts($product);

    echo $product->getId(); //Main configurable product ID
    echo $product->getName(); //Main Configurable Name

    foreach ($usedProducts  as $child) {
        echo $child->getId()."</br>"; //Child Product Id  
        echo $child->getName()."</br>"; //Child Product Name
    }

Used the above code. But error occurs for getUsedProducts. please help me to find a solution.

Answer 1

Will get the answer by this code itself afeter di:compile

$objectManager = \Magento\Framework\App\ObjectManager::getInstance();

$product = $objectManager->get('Magento\Framework\Registry')->registry('current_product');//get current product

$productTypeInstance = $product->getTypeInstance();

$usedProducts = $productTypeInstance->getUsedProducts($product);

echo $product->getId(); //Main configurable product ID
echo $product->getName(); //Main Configurable Name

foreach ($usedProducts  as $child) {
    echo $child->getId()."</br>"; //Child Product Id  
    echo $child->getName()."</br>"; //Child Product Name
}

Answer 2

Firstly, never use objectManager like you did in your phtml or in any block class. You should always use automatic constructor's dependency injection system.

I suggest you to utilise Magento 2's Service Contract, if you'd like to do it Magento way. There might be lots of methods available ported from Magento 1 but those will be removed in future updates - 'getUsedProducts' is one of them.

Add the following code in your block class:

use Magento\Catalog\Api\ProductRepositoryInterface;
use Magento\ConfigurableProduct\Api\LinkManagementInterface;
use Magento\Framework\Api\SearchCriteriaBuilder;
use Magento\Framework\Registry;

  /**
   * @var ProductRepositoryInterface
   */

    protected $productRepository;

   /**
    * @var SearchCriteriaBuilder
    */
    protected $searchCriteriaBuilder;

    /**
     * @var LinkManagementInterface
     */
    protected $linkManagement;

    /**
     * @var LinkManagementInterface
     */
    protected $registry;

    /**
     * @param LinkManagementInterface $linkManagement
     * @param ProductRepositoryInterface $productRepository
     * @param SearchCriteriaBuilder $searchCriteriaBuilder
     * @param Registry $registry
     */
    public function __construct(
        LinkManagementInterface $linkManagement,
        ProductRepositoryInterface $productRepository,
        SearchCriteriaBuilder $searchCriteriaBuilder,
        Registry $registry
    ) {
        $this->linkManagement = $linkManagement;
        $this->productRepository = $productRepository;
        $this->searchCriteriaBuilder = $searchCriteriaBuilder;
        $this->registry = $registry;
        parent::__construct();
    }

    public function getChilds() 
    {
      $parentId = $this->registry->registry('current_product')->getId();
      $searchCriteria = $this->searchCriteriaBuilder
            ->addFilter('type_id', 'configurable')
            ->addFilter('entity_id', $parentId)
            ->create();

      $configurableProducts = $this->productRepository
            ->getList($searchCriteria);

      foreach ($configurableProducts->getItems() as $configurableProduct) {
        $childProducts = $this->linkManagement
            ->getChildren($configurableProduct->getSku());
      }
      return $childProducts;
    }

Now you can get the $childProducts collection in your blocks phtml something like:

$childProducts = $block->getChilds();
foreach ($childProducts as $child) {
  $childId = $child->getId();
}
echo $childId();