How to Override Block, Model, Controller in Magento2

Magento 2 introduced new concept called “preference” to override class.

What is Preference?

Preference are similar to class rewrites in Magento 1. Preference is used for override/rewrite the class.Preference configurations are falls inside the di.xml file of module.

Preferences are also answerable for Abstraction-Implementation mappings. ObjectManager used the preference to identify the default implementation class for the respective interface. Example: Magento\Framework\Logger\Monolog is the default implementation class for the Psr\Log\LoggerInterface

Let’s we start to learn overriding blocks, models and controllers in magento2

Overriding Block

Step 1: You need to create di.xml file in directory Mageclues\Override\etc and add configuration with preference.

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Acl/etc/acl.xsd">
	<preference for="Magento\Catalog\Block\Product\ListProduct" type="Mageclues\Override\Block\Rewrite\Product\ListProduct" />
</config>

Step 2: You need to create ListProduct.php Block file in directory Mageclues\Override\Block\Rewrite\Product

<?php
	namespace Mageclues\Override\Block\Rewrite\Product;

	class ListProduct extends \Magento\Catalog\Block\Product\ListProduct
	{
		public function _getProductCollection()
		{
			// you can add/append your custom code here
		}
	}

Overriding Model

Step 1: You need to create di.xml file in directory Mageclues\Override\etc and add configuration with preference.

<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
 <preference for="Magento\Catalog\Model\Product" type="Mageclues\Override\Model\Rewrite\Catalog\Product" />
</config>

Step 2: You need to create Product.php Model file in directory Mageclues\Override\Model\Rewrite\Catalog

<?php
	namespace Mageclues\Override\Model\Rewrite\Catalog;

	class Product extends \Magento\Catalog\Model\Product
	{
		public function isSalable()
		{
			// you can add/append your custom code here
			return parent::isSalable();
		}
	}

Overriding Controller

Step 1: You need to create di.xml file in directory Mageclues\Override\etc and add configuration with preference.

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
	<preference for="Magento\Catalog\Controller\Product\View" type="Mageclues\Override\Controller\Rewrite\Product\View" />
</config>

Step 2: You need to create View.php controller file in directory Mageclues\Override\Controller\Rewrite\Product

<?php
	namespace Mageclues\Override\Controller\Rewrite\Product;

	class View extends \Magento\Catalog\Controller\Product\View
	{
		public function execute()
		{
			// you can add/append your custom code here
			return parent::execute();
		}
	}

I thought you understand about how to override class. you can override other Block, Model and Controller classes.

I hope this blog is useful for you. Please left comment if you have any confusion.

Thank you):