Magento2: Block not created from controller

Question

How to create block from controller by ajax method?

    $result = $this->resultJsonFactory->create();
    $resultPage = $this->_resultPageFactory->create();
    $block = $resultPage->getLayout()
        ->createBlock('Module\Ajaxcart\Block\BuildProductInfo')
        ->setTemplate('Module_Ajaxcart::buildproductinfo.phtml')
        ->toHtml();

Showing Cache Exception Error

Answer 1

Try This :-

protected $resultPageFactory;

public function __construct(
    Magento\Framework\View\Result\PageFactory $resultPageFactory
){
      $this->resultPageFactory = $resultPageFactory;
} 
public function execute() 
{

     $layout = $this->resultPageFactory->create();

     $block = $layout->getLayout()
                    ->createBlock('Module\Ajaxcart\Block\BuildProductInfo')
                    ->setTemplate('Module_Ajaxcart::buildproductinfo.phtml')
                    ->toHtml();
}

Answer 2

You don't send a response from your ajax controller.

result factory type should be json

$resultJson = $this->resultFactory->create(ResultFactory::TYPE_JSON);

Code Sample:

<?php
namespace Magento\Contact\Controller\Index;

use Magento\Framework\Controller\ResultFactory;

class AjaxCall extends \Magento\Framework\App\Action\Action
{
    public function __construct(
       \Magento\Framework\App\Action\Context $context
    ) {
        parent::__construct($context);
    }
    public function execute() {
        $this->_view->loadLayout();
        $layout = $this->_view->getLayout();
        $customBlock = $layout->createBlock(
            \Magento\Contact\Block\ContactForm::class,
            'ajax.contact-us',
            ['data' => ['id' => 'test']]
        )->setTemplate('Magento_Contact::form.phtml');

        $resultJson = $this->resultFactory->create(ResultFactory::TYPE_JSON);
        return $resultJson->setData(
                [
                    'html' => $customBlock->toHtml(),
                    'message' => __('my message')
                ]
            );
    }

}