Fatal error: Uncaught TypeError: Argument 1 passed

Question

Please anyone see my code and resolve this issue

Fatal error: Uncaught TypeError: Argument 1 passed to MyClass::__construct() must implement interface Magento\Framework\Session\SessionManagerInterface, none given, called in /home/dukaania/public_html/testing2/vendor/magento/module-checkout/view/frontend/templates/cart/shipping.phtml on line 132 and defined in /home/dukaania/public_html/testing2/vendor/magento/module-checkout/view/frontend/templates/cart/shipping.phtml:109 Stack trace: #0

    use Magento\Framework\Session\SessionManagerInterface as CoreSession;

    class MyClass
    {

        protected $_coreSession;

        public function __construct(CoreSession $coreSession) 
        {
            $this->_coreSession = $coreSession;

        }

      public function setValue($total_cost){
        $this->_coreSession->start();
        $this->_coreSession->setMessage($total_cost);


    }

    public function getValue(){
        $this->_coreSession->start();
        return $this->_coreSession->getMessage();


    }


}

$myclas = new MyClass();

 $myclas.setValue($total_cost);     
 echo $myclas.getValue();

Answer 1

You issue at $myclas = new MyClass();

To initialize this class you have to use the object manager or have to inject that class to your class.

$objectManager = \Magento\Framework\App\ObjectManager::getInstance();
$myclass = $objectManager->create('{NameSpaceofClass}\MyClass');

Answer 2

simply run di compile

php -dmemory_limit=6G bin/magento setup:di:compile

AND

php bin/magento cache:clean && php bin/magento cache:flush

OR just run this command

If you are using Magento 2.1.9 or less than clear/remove

rm -rf var/generation folder

for above magento version run below command

rm -rf generated

and check your output again

Answer 3

Please replace your constructor with this and let's check if it works,

 public function __construct(
       \Magento\Framework\Session\SessionManagerInterface $coreSession
    ) {
        $this->_coreSession = $coreSession;
    }

As we are directly passing the SessionManagerInterface class in the constructor we don't need to include it.

Now run the following commands

php bin/magento setup:upgrade

php bin/magento setup:static-content:deploy

Answer 4

Set/Get/Unset Value in Core Session:

protected $_coreSession;

public function __construct(
    -----
    \Magento\Framework\Session\SessionManagerInterface $coreSession
    ){
    $this->_coreSession = $coreSession;
    ----
}

public function setValue($total_cost){
    $this->_coreSession->start();
    $this->_coreSession->setMessage($total_cost);
}

public function getValue(){
    $this->_coreSession->start();
    return $this->_coreSession->getMessage();
}

public function unSetValue(){
    $this->_coreSession->start();
    return $this->_coreSession->unsMessage();
}

after this Run this SSH Command

  1. rm -rf var/*
  2. rm -rf generated/*