Custom Message Not Show in Cms Page in Magento 2

Question

I have created custom contact form and call in cms page. I submit all form field with controller and add success message after submit and redirect back to cms page but success message not appeared in my cms page.

My Controller.php

<?php

namespace Vendor\Module\Controller;

use Magento\Framework\Controller\ResultFactory;

class Form extends \Magento\Framework\App\Action\Action
{
    public function execute()
    {
        $post = (array) $this->getRequest()->getPost();

        if (!empty($post)) {


            $this->messageManager->addSuccessMessage('My custom Message !'); // This message not appeared in cms page after redirect

            $resultRedirect = $this->resultFactory->create(ResultFactory::TYPE_REDIRECT);
            $resultRedirect->setUrl('/mycmspage');

            return $resultRedirect;
        }

        $this->_view->loadLayout();
        $this->_view->renderLayout();
    }
}

I also add cms_index_index.xml

<?xml version="1.0"?>
<page xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:View/Layout/etc/page_configuration.xsd">
    <referenceContainer name="page.messages">
        <block class="Magento\Framework\View\Element\Messages" name="messages" as="messages"/>
    </referenceContainer>
</page>

Help Appreciated...

Answer 1

Update your message code with below line:

 $this->messageManager->addSuccess('My custom Message !');

Answer 2

Try to use following code

<?php

namespace Vendor\Module\Controller;

use Magento\Framework\Controller\ResultFactory;

class Form extends \Magento\Framework\App\Action\Action
{
    protected $_messageManager;

    public function __construct(
        \Magento\Framework\View\Element\Template\Context $context, 
        \Magento\Framework\Message\ManagerInterface $messageManager
    ) {
        parent::__construct($context);
        $this->_messageManager = $messageManager;
    }

    public function execute()
    {
        $post = (array) $this->getRequest()->getPost();

        if (!empty($post)) {


            $this->messageManager->addSuccessMessage('My custom Message !'); // This message not appeared in cms page after redirect

            $resultRedirect = $this->resultFactory->create(ResultFactory::TYPE_REDIRECT);
            $resultRedirect->setUrl('/mycmspage');

            return $resultRedirect;
        }

        $this->_view->loadLayout();
        $this->_view->renderLayout();
    }
}