Author: m@g3m@nk3y$

If you want to restrict customer to checkout based on your criteria (condition), then this article is your answer.

For example if you want to restrict customer when cart total less then $300, this method is worth to give a try.

Here we are using Magemonkeys as Vendor name and CheckoutRestriction as the name of a module. You can change this according to your Vendor and Module name.

Step 1: Create Registration

Create registration.php file in the app/code/Magemonkeys/CheckoutRestriction folder with the following code.

<?php
MagentoFrameworkComponentComponentRegistrar::register(
    MagentoFrameworkComponentComponentRegistrar::MODULE,
    'Magemonkeys_CheckoutRestriction',
    __DIR__
);

Step 2: Create a module

Create a module.xml file in the app/code/Magemonkeys/CheckoutRestriction/etc folder with the following code.

<?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="Magemonkeys_CheckoutRestriction" setup_version="1.0.0">
        <sequence>
            <module name="Magento_Checkout"/>
        </sequence>
    </module>
</config>

Step 3: Create a di.xml for front-end

Create a di.xml file in the app/code/Magemonkeys/CheckoutRestriction/etc/frontend folder with the following code.

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
    // plugin restrict checkout
    <type name="MagentoCheckoutControllerIndexIndex">
        <plugin name="restrictcheckout" type="MagemonkeysCheckoutRestrictionPluginCheckoutControllerRestrict"/>
    </type>
</config>

Step 4: Create a Plugin file

Create a Restrict.php file in the app/code/Magemonkeys/CheckoutRestriction/Plugin/Checkout/Controller with the following code.

<?php
 
namespace MagemonkeysCheckoutRestrictionPluginCheckoutController;
 
use MagentoFrameworkControllerResultRedirectFactory;
use MagentoFrameworkMessageManagerInterface;
use MagentoFrameworkUrlFactory;
use MagentoCheckoutControllerIndexIndex;
use MagentoCheckoutModelCart;
 
class Restrict
{
    private $urlModel;
    private $resultRedirectFactory;
    private $messageManager;
 
    public function __construct(
        UrlFactory $urlFactory,
        RedirectFactory $redirectFactory,
        ManagerInterface $messageManager,
        Cart $cart
    ) {
    
        $this->urlModel = $urlFactory;
        $this->resultRedirectFactory = $redirectFactory;
        $this->messageManager = $messageManager;
        $this->cart = $cart;
    }
 
    public function aroundExecute(
        Index $subject,
        Closure $proceed
    ) {
    
        $this->urlModel = $this->urlModel->create();

        
        //add your logic here
        $subTotal = $this->cart->getQuote()->getSubtotal();

        if(!empty($subTotal) && $subTotal < 300){
            $this->messageManager->addErrorMessage(__("Unable to checkout as one or more products have not met their minimum purchase theshold."));
            $defaultUrl = $this->urlModel->getUrl('checkout/cart/', ['_secure' => true]);
            $resultRedirect = $this->resultRedirectFactory->create();
            return $resultRedirect->setUrl($defaultUrl);
        }
          
        return $proceed();
    }
}

Here is screenshot which shows error message when some one trying to click on checkout and subtotal less then $300

You can replace 300$ with your favorable amount and use accordingly.

If you want to add custom column in product grid, then follow below step to create custom module to add custom column in grid.

Step 1) app/code/Magemonkeys/SalesordercreategridCustomattr/registration.php

<?php
MagentoFrameworkComponentComponentRegistrar::register(
    MagentoFrameworkComponentComponentRegistrar::MODULE,
    'Magemonkeys_SalesordercreategridCustomattr',
    __DIR__
);

Step 2) app/code/Magemonkeys/SalesordercreategridCustomattr/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="Magemonkeys_SalesordercreategridCustomattr" setup_version="1.0.0">
    </module>
</config>

Step 3) app/code/Magemonkeys/SalesordercreategridCustomattr/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="MagentoSalesBlockAdminhtmlOrderCreateSearchGrid" type="MagemonkeysSalesordercreategridCustomattrBlockAdminhtmlOrderCreateSearchGrid" />
</config>

Step 4) app/code/Magemonkeys/SalesordercreategridCustomattr/Block/Adminhtml/Order/Create/Search/Grid.php

<?php
namespace MagemonkeysSalesordercreategridCustomattrBlockAdminhtmlOrderCreateSearch;

class Grid extends MagentoSalesBlockAdminhtmlOrderCreateSearchGrid
{
    /**
     * @param MagentoBackendBlockTemplateContext $context
     * @param MagentoBackendHelperData $backendHelper
     * @param MagentoCatalogModelProductFactory $productFactory
     * @param MagentoCatalogModelConfig $catalogConfig
     * @param MagentoBackendModelSessionQuote $sessionQuote
     * @param MagentoSalesModelConfig $salesConfig
     * @param array $data
     */
    public function __construct(
        MagentoBackendBlockTemplateContext $context,
        MagentoBackendHelperData $backendHelper,
        MagentoCatalogModelProductFactory $productFactory,
        MagentoCatalogModelConfig $catalogConfig,
        MagentoBackendModelSessionQuote $sessionQuote,
        MagentoSalesModelConfig $salesConfig,
        array $data = []
    )
    {
        $this->_productFactory = $productFactory;
        $this->_catalogConfig = $catalogConfig;
        $this->_sessionQuote = $sessionQuote;
        $this->_salesConfig = $salesConfig;
        parent::__construct($context, $backendHelper, $productFactory, $catalogConfig, $sessionQuote, $salesConfig, $data);
    }

    /**
     * Prepare collection to be displayed in the grid
     *
     * @return $this
     */
    protected function _prepareCollection()
    {
        $attributes = $this->_catalogConfig->getProductAttributes();
        /* @var $collection MagentoCatalogModelResourceModelProductCollection */
        $collection = $this->_productFactory->create()->getCollection();
        $collection->setStore(
            $this->getStore()
        )->addAttributeToSelect(
            $attributes
        )->addAttributeToSelect(
            'sku'
        )->addStoreFilter()->addAttributeToFilter(
            'type_id',
            $this->_salesConfig->getAvailableProductTypes()
        )->addAttributeToSelect(
            'gift_message_available'
        );

        $collection->joinField(
            'qty_in_stock',
            'cataloginventory_stock_item',
            'qty',
            'product_id=entity_id',
            '{{table}}.stock_id=1 AND {{table}}.website_id=0',
            'left'
        );

        $this->setCollection($collection);

        $parent = get_parent_class($this);
        $parentclass = get_parent_class($parent);
        return $parentclass::_prepareCollection();
    }

    /**
     * Prepare columns
     *
     * @return $this
     */
    protected function _prepareColumns()
    {
        $this->addColumn(
            'entity_id',
            [
                'header' => __('ID'),
                'sortable' => true,
                'header_css_class' => 'col-id',
                'column_css_class' => 'col-id',
                'index' => 'entity_id'
            ]
        );
        $this->addColumn(
            'name',
            [
                'header' => __('Product'),
                'renderer' => MagentoSalesBlockAdminhtmlOrderCreateSearchGridRendererProduct::class,
                'index' => 'name'
            ]
        );
        $this->addColumn('sku', ['header' => __('SKU'), 'index' => 'sku']);
        $this->addColumn('customsku', ['header' => __('Custom SKU'), 'index' => 'customsku']);
        $this->addColumn(
            'price',
            [
                'header' => __('Price'),
                'column_css_class' => 'price',
                'type' => 'currency',
                'currency_code' => $this->getStore()->getCurrentCurrencyCode(),
                'rate' => $this->getStore()->getBaseCurrency()->getRate($this->getStore()->getCurrentCurrencyCode()),
                'index' => 'price',
                'renderer' => MagentoSalesBlockAdminhtmlOrderCreateSearchGridRendererPrice::class
            ]
        );

        $this->addColumn(
            'in_products',
            [
                'header' => __('Select'),
                'type' => 'checkbox',
                'name' => 'in_products',
                'values' => $this->_getSelectedProducts(),
                'index' => 'entity_id',
                'sortable' => false,
                'header_css_class' => 'col-select',
                'column_css_class' => 'col-select'
            ]
        );

        $this->addColumn(
            'qty',
            [
                'filter' => false,
                'sortable' => false,
                'header' => __('Quantity'),
                'renderer' => MagentoSalesBlockAdminhtmlOrderCreateSearchGridRendererQty::class,
                'name' => 'qty',
                'inline_css' => 'qty',
                'type' => 'input',
                'validate_class' => 'validate-number',
                'index' => 'qty'
            ]
        );

        $this->addColumn(
            'qty_in_stock',
            [
                'header' => __('Stock'),
                'type' => 'number',
                'index' => 'qty_in_stock'
            ]
        );

        $parent = get_parent_class($this);
        $parentclass = get_parent_class($parent);
        return $parentclass::_prepareColumns();
    }
}

Step 5 : After place above code, please run below mentioned commands

- php bin/magento setup:upgrade
- php bin/magento setup:static-content:deploy
- php bin/magento cache:clean

That’s it…

Now refresh your sales order, create grid page and see that your custom column will be reflecting there.