Magento 2 Custom module error when changing constructor

Question

I am creating a new custom module for Magento 2.1.x which some includes some Blocks. In one of them, at the beginning of the development, the constructor had onlt two parameters:

use \Magento\Framework\View\Element\Template;
class Products extends Template
{
 public function __construct(
 \Magento\Backend\Block\Template\Context $context,
 array $data = []
 )
 {
 parent::__construct($context, $data);
 }
}

Lately I had to add a new parameter to the constructor

use \Magento\Framework\View\Element\Template;
class Products extends Template
{
 protected $_productCollectionFactory;
 public function __construct(
 \Magento\Backend\Block\Template\Context $context,
 \Magento\Catalog\Model\ResourceModel\Product\CollectionFactory $productCollectionFactory,
 array $data = []
 )
 {
 $this->_productCollectionFactory = $productCollectionFactory;
 parent::__construct($context, $productCollectionFactory);
 }
}

If I reload the frontend I am getting the following error:

Fatal error: Uncaught TypeError: Argument 2 passed to Magento\Framework\View\Element\Template::__construct() must be of the type array, object given, called in ...

What should I do to make the new constructor work? Should I delete something? Should I run some command via CLI? (I am using the developer mode)

• Aman Alam: Your parent constructor argument should look like this parent::__construct($context, $data); and if you want to get product collection on template create a function called getProductCollection or yourFunctionName and return product collection like return $this->_productCollectionFactory this may resolve your issue.
• giani.sim: Yeah, you are right! It is just a typo error.

Answer 1

Your parent constructor argument should look like this parent::__construct($context, $data); and if you want to get product collection on template create a function called getProductCollection or yourFunctionName and return product collection like return $this->_productCollectionFactory and call that function in template you will get collection.

You block should look like :

use \Magento\Framework\View\Element\Template;
class Products extends Template
{
 protected $_productCollectionFactory;
 public function __construct(
 \Magento\Backend\Block\Template\Context $context,
 \Magento\Catalog\Model\ResourceModel\Product\CollectionFactory $productCollectionFactory,
 array $data = []
 )
 {
 $this->_productCollectionFactory = $productCollectionFactory;
 parent::__construct($context, $data);
 }
 //call $this->getProductCollection() will return product collection in template file.
 public function getProductCollection(){
 return $this->_productCollectionFactory;
 }
}