Magento 2: How to set a custom price of a product?

Question

In Magento 2, I need to set the custom price of a product pro-grammatically when admin creates an order from backend.

For example, in this page

'www.site.com/admin/sales/order_create/index/key/a0f4c...

when an admin click's 'Add Selected Product(s) to Order' (after clicking 'add products'), I want to compute prices of that selected products through some formula then assign these prices as a custom price to that products.

So what I really need is a piece of code by which Magento assigns custom price to product.

Answer 1

Create events.xml file at app/code/YourNamespace/YourModule/etc/frontend

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Event/etc/events.xsd">
    <event name="checkout_cart_product_add_after">
        <observer name="custompricemodule" instance="YourNamespace\YourModule\Observer\CustomPrice" />
    </event>
</config>

Create CustomPrice.php file at app/code/YourNamespace/YourModule/Observer

<?php
namespace YourNamespace\YourModule\Observer;

use Magento\Framework\Event\ObserverInterface;
use Magento\Framework\App\RequestInterface;

class CustomPrice implements ObserverInterface
{
    public function execute(\Magento\Framework\Event\Observer $observer) {
        $item = $observer->getEvent()->getData('quote_item');         
        $item = ( $item->getParentItem() ? $item->getParentItem() : $item );
        $price = 100; //set your price here
        $item->setCustomPrice($price);
        $item->setOriginalCustomPrice($price);
        $item->getProduct()->setIsSuperMode(true);
    }

}

Hope this will help you :)