Although I use the correct namespace a wrong instance is passed to the constructor

Question

I have a block php file. Block File Code:

<?php
namespace Vendor\SampleModule1\Block;
use Magento\Framework\View\Element\Template;
use Magento\Framework\View\Element\Template\Context;
use Vendor\SampleModule1\Model\ResrouceModel\Item\Collection;
use Vendor\SampleModule1\Model\ResrouceModel\Item\CollectionFactory;
class Hello extends Template
{
 private $collectionFactory;
 public function __construct(
 Context $context,
 CollectionFactory $collectionFactory,
 array $data =[]
 )
 {
 $this->collectionFactory = $collectionFactory;
 parent::__construct($context, $data);
 }
 /**
 * @return \Vendor\SampleModule1\Model\Item[]
 */
 public function getItems()
 {
 return $this->collectionFactory->create()->getItems();
 }
}

When I try to see the view the error is

Fatal error: Uncaught TypeError: Argument 1 passed to Vendor\SampleModule1\Block\Hello::__construct() must be an instance of Magento\Framework\View\Element\Template\Context, instance of Magento\Framework\ObjectManager\ObjectManager given ....

How is that possible ? ? ?

• Keyur Shah: try to do di:compile
• Khoa Truong: Did you try to remove var/generation folder?

Answer 1

You need to compile your code after you have done changes.

Please do

php bin/magento setup:di:compile

• Lachezar Raychev: Thank you, I will try it. It wasn't mentioned at all in the tutorial.
• Rajeev K Tomy: Yes, they are not going to do that coz, they consider it as an "already knowing" fact (by every Magento developer). We all gone through this confusion and found out the answer ourself :)
• Lachezar Raychev: but on every tutorial the commande chace:flush is used :) whatever ... just weird, thank you
• Prince Patel: @LachezarRaychev Check this answer for when you should run which commands: magento.stackexchange.com/a/184927/35758
• Rajeev K Tomy: @PrincePatel Yes, that's a nice reference point.