Magento 2.3 Inject helper into controller object type error?

Question

Sorry I am new to M2, I am having error whenever I load helper class into controller. I searched every online but no luck. Here is the setup and error when I load

Setup: Magento 2.3 Server Centos 7 / PHP7.2 / Local VM

Error Trace

1 exception(s): Exception #0 (Magento\Framework\Exception\RuntimeException): Type Error occurred when creating object: Custom\Payment\Controller\Index\Index\Interceptor

Exception #0 (Magento\Framework\Exception\RuntimeException): Type Error occurred when creating object: Custom\Payment\Controller\Index\Index\Interceptor #0 /var/www/html/vendor/magento/framework/ObjectManager/Factory/Dynamic/Developer.php(66): Magento\Framework\ObjectManager\Factory\AbstractFactory->createObject('Custom\Payment\...', Array) #1 /var/www/html/vendor/magento/framework/ObjectManager/ObjectManager.php(56): Magento\Framework\ObjectManager\Factory\Dynamic\Developer->create('Custom\Payment\...', Array) #2 /var/www/html/vendor/magento/framework/App/ActionFactory.php(44): Magento\Framework\ObjectManager\ObjectManager->create('Custom\Payment\...') #3 /var/www/html/vendor/magento/framework/App/Router/Base.php(304): Magento\Framework\App\ActionFactory->create('Custom\Payment\...') #4 /var/www/html/vendor/magento/framework/App/Router/Base.php(165): Magento\Framework\App\Router\Base->matchAction(Object(Magento\Framework\App\Request\Http), Array) #5 /var/www/html/vendor/magento/framework/App/FrontController.php(95): Magento\Framework\App\Router\Base->match(Object(Magento\Framework\App\Request\Http)) #6 /var/www/html/vendor/magento/framework/Interception/Interceptor.php(58): Magento\Framework\App\FrontController->dispatch(Object(Magento\Framework\App\Request\Http)) #7 /var/www/html/vendor/magento/framework/Interception/Interceptor.php(138): Magento\Framework\App\FrontController\Interceptor->___callParent('dispatch', Array) #8 /var/www/html/vendor/magento/module-store/App/FrontController/Plugin/RequestPreprocessor.php(94): Magento\Framework\App\FrontController\Interceptor->Magento\Framework\Interception{closure}(Object(Magento\Framework\App\Request\Http)) #9 /var/www/html/vendor/magento/framework/Interception/Interceptor.php(135): Magento\Store\App\FrontController\Plugin\RequestPreprocessor->aroundDispatch(Object(Magento\Framework\App\FrontController\Interceptor), Object(Closure), Object(Magento\Framework\App\Request\Http)) #10 /var/www/html/vendor/magento/module-page-cache/Model/App/FrontController/BuiltinPlugin.php(69): Magento\Framework\App\FrontController\Interceptor->Magento\Framework\Interception{closure}(Object(Magento\Framework\App\Request\Http)) #11 /var/www/html/vendor/magento/framework/Interception/Interceptor.php(135): Magento\PageCache\Model\App\FrontController\BuiltinPlugin->aroundDispatch(Object(Magento\Framework\App\FrontController\Interceptor), Object(Closure), Object(Magento\Framework\App\Request\Http)) #12 /var/www/html/vendor/magento/framework/Interception/Interceptor.php(153): Magento\Framework\App\FrontController\Interceptor->Magento\Framework\Interception{closure}(Object(Magento\Framework\App\Request\Http)) #13 /var/www/html/generated/code/Magento/Framework/App/FrontController/Interceptor.php(26): Magento\Framework\App\FrontController\Interceptor->___callPlugins('dispatch', Array, NULL) #14 /var/www/html/vendor/magento/framework/App/Http.php(135): Magento\Framework\App\FrontController\Interceptor->dispatch(Object(Magento\Framework\App\Request\Http)) #15 /var/www/html/generated/code/Magento/Framework/App/Http/Interceptor.php(24): Magento\Framework\App\Http->launch() #16 /var/www/html/vendor/magento/framework/App/Bootstrap.php(258): Magento\Framework\App\Http\Interceptor->launch() #17 /var/www/html/index.php(39): Magento\Framework\App\Bootstrap->run(Object(Magento\Framework\App\Http\Interceptor)) #18 {main}

Helper Code

namespace Custom\Payment\Helper;

use Magento\Framework\App\Helper\AbstractHelper;

class General extends AbstractHelper
{

    public function RandomFunc()
       {
               echo "This is Helper in Magento 2";
       }

}

Controller Code

namespace Custom\Payment\Controller\Index;

use Custom\Payment\Helper\General as CustomHelper;
use Magento\Framework\App\Action\Action;

class Index extends Action
{
    protected $helper;

    public function __construct(
        CustomHelper $helper
    ) {
        $this->helper = $helper;
    }

    public function execute()
    {
        $this->helper->RandomFunc();
    }
}

Anyone could enlighten me where I did wrong?

Thank you!

Answer 1

You have an issue at __construct(.

You must pass the context object \Magento\Framework\App\Action\Context $context to the parent class Magento\Framework\App\Action\Action

public function __construct(
\Magento\Framework\App\Action\Context $context,
    CustomHelper $helper
) {
    $this->helper = $helper;
parent::__construct($context);
}

after these changes, when in developer mode, just remove the folders under var/generation/ or generated/ as the documentation suggests

or run setup:di:compile when in production mode

---

Answer 2

Just Remove the Generation folder or in version 2.2 remove the generated folder.

rm -rf generated/

Flush the cache. It should work then. Its because the interceptor file needs to be re-created or refresh.

Answer 3

In addition to Amit Bera's answer, make sure that if you're adding any new parameters to the __construct() method that you add them before any parameters with default values (like null) defined.

Answer 4

Run the di complie and cache flush commands

php bin/magento s:d:c

Php bin/magento c:c

Php bin/magento c:f

Answer 5

The interceptor file needs to be re-create. So kindly run di:compile and clean cache

php bin/magento setup:di:compile
php bin/magento  c:f

//Or 

rm -rf generated/

Its worked for me