How to Instantiate a Model in Magento 2

We all know that in Magento 1 We can easily instantiate model using Mage::getModel and Mage::getSingleton methods. But instantiate a model in Magento 2 something different.

In Magento 2 we can instantiate a model using Object Manager. Yes, you heard it correctly, ObjectManager is a replacement for getModel and getSingleton Method.

There are two approaches you can invoke ObjectManager in Magento 2 to instantiate a model or to get the model collection.

Approach 1: Using ObjectManager Directly anywhere

Let’s say we want to get product collection in our Magento 2 custom module phtml file. You can get this using below code.

<?php 
$objectManager = \Magento\Framework\App\ObjectManager::getInstance();
$productCollection = $objectManager->create('Magento\Catalog\Model\ResourceModel\Product\CollectionFactory');
$productCollection->addAttributeToSelect('*');
$productCollection->load();
foreach ($productCollection as $product) {
echo "<pre>";
print_r($product->getData());     
}

<?php

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

$productCollection = $objectManager->create('Magento\Catalog\Model\ResourceModel\Product\CollectionFactory');

$productCollection->addAttributeToSelect('*');

$productCollection->load();

foreach ($productCollection as $product) {

echo "<pre>";

print_r($product->getData());

}

Approach 2: Inject model into Constructor and instantiate

Second and recommended approach of instantiating a model in Magento 2 is using a constructor. To get product collection in your custom phtml file, You need to create a block file inject the product model into the constructor of that block file.

Step 1: Create Block.php file
For example our block file Index.php is under app/code/Codextblog/Pcollection/Block/Index

<?php
namespace Codextblog\Pcollection\Block\Index;
class Index extends \Magento\Framework\View\Element\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);
}
public function getProductCollection()
{
$collection = $this->_productCollectionFactory->create();
$collection->addAttributeToSelect('*');
return $collection;
}
}

<?php

namespace Codextblog\Pcollection\Block\Index;

class Index extends \Magento\Framework\View\Element\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);

}

public function getProductCollection()

{

$collection = $this->_productCollectionFactory->create();

$collection->addAttributeToSelect('*');

return $collection;

}

Step 2: Call getProductCollection in your phtml file
For example our phtml file Index.phtml is under app/code/Codextblog/Pcollection/view/frontend/templates

<?php
$pCollection = $block->getProductCollection();
foreach ($pCollection as $product) {
echo "<pre>";
print_r($product->getData());     
}

<?php

$pCollection = $block->getProductCollection();

foreach ($pCollection as $product) {

echo "<pre>";

print_r($product->getData());

}

This is how you can get product collection in your custom phtml file.

Which Approach to use?

Well, it is a very tedious task to go with approach 2 to just get product collection. But as per Magento Official doc, you should always use constructor method to instantiate a model in Magento 2 to maintain the implementation of Dependency Injection.

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