Question about Override block from design ?

[awes_ome]

Is it possible to override a block (in my case i need to extend a core Block) from app/design/frontend/Vendor/ThemeName (theme folder) or do i have to do it from app/code/Vendor/ModuleName? And if so can anyone provide a simple example still new to magento.

I would like to do it this way because i would like it to be part of the theme.

[nisha_jangid]

Hello @awes_ome 

You have to create your own module under app/code folder. For that you have to create some file :

app/code/Vendor/Module/etc/module.xml

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Module/etc/module.xsd">
    <module name="Vendor_Module" setup_version="1.0.0"></module>
</config>

app/code/Vendor/Module/registration.php

<?php

\Magento\Framework\Component\ComponentRegistrar::register(
  \Magento\Framework\Component\ComponentRegistrar::MODULE,
  'Vendor_Module',
  __DIR__
);

After that we have to use preference to override the class in Magento 2.

app/code/Vendor/Module/etc/di.xml

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
  <preference for="Magento\Theme\Block\Html\Topmenu" type="Vendor\Module\Block\Html\Topmenu" />
</config>

app/code/Vendor/Module/Block/Html/Topmenu.php

<?php

namespace Vendor\Module\Block\Html;

class Topmenu extends \Magento\Theme\Block\Html\Topmenu
{

    protected function _addSubMenu($child, $childLevel, $childrenWrapClass, $limit)
    {

    }

}

Hope it will work for you.

If my answer is useful, please Accept as Solution & give Kudos.