Magento 2: How to call helper function in Controller

Question

How to call helper function in controller:-

I have use below code:-

class Index extends \Magento\Framework\App\Action\Action
{
    protected $helperData;

    public function __construct(
         ....
        \{Vendor}\{Module}\Helper\Data $helperData,
        ....
    ) {
        ....
        $this->helperData = $helperData;
        ....
    }       

    public function execute()
    {
        $this->helperData-><functionName>();
        return;     
    }
}

this code give me error as below:-

Uncaught TypeError: Argument 2 passed to {Vendor}\{Module}\Controller\Callforprice\Index::__construct() must be an instance of {Vendor}\{Module}\Helper\Data, none given, called in

Answer 1

Code is correct. This happened to me many times. I have cleared /var/generation directory when altering constructor parameters.

Hope this helps.

Answer 2

You can try below code..

 class Index extends \Magento\Framework\App\Action\Action
  {

protected $helperData;

public function __construct(
     \Magento\Framework\App\Action\Context $context,
    \{Vendor}\{Module}\Helper\Data $helperData

) {

    $this->helperData = $helperData;
    parent::__construct($context, $helperData);

}

public function execute()
{
    $this->helperData-><functionName>();
    return;     
}
}

Then, Clear Cache and try it, let me know if you have issue...

Answer 3

These types of errors (Uncaught TypeError: Argument 2 passed to...) occures when you add more parameters to constructor, it would fix after you run di compile command to regenerate your code in generated directory, run following command and it will fix.

php -dmemory_limit=1G bin/magento setup:upgrade
php -dmemory_limit=1G bin/magento setup:di:compile
php -dmemory_limit=1G bin/magento setup:static-content:deploy -f
php bin/magento cache:clean