How to do selected single product should be purchase alone?

[Aveeva]

I have one restricted product, here how to do selected single product should be purchased alone? No other products are eligible to add add-to-cart if this product available in the add-to-cart, same if other products available in add-to-cart this product not eligible to add add-to-cart. How to achieve this in Magento?

[Vimal Kumar]

Hi @Aveeva,

You can do it using event observer in magento.

You can use "checkout_cart_product_add_before" event and in observer you can check your current product is already exist or not in quote. Then you restrict as per your conditions.

create-checkout_cart_product_add_before-observer-magento

To get Quote in observer.

$quote = Mage::getSingleton('checkout/session')->getQuote();
$cartItems = $quote->getAllVisibleItems();
foreach ($cartItems as $item) {
    $productId = $item->getProductId();     
    // Do something more
}

I hope it will help you.

[Aveeva]

@Vimal Kumar I am new to magento, where i can add above code?

[Vimal Kumar]

Hi @Aveeva 

I have a download custom module from below url.

Module Download

You need to make change in :

app/code/local/VP/CartOverride/Model/Observer.php

[Aveeva]

@Vimal Kumar  What i need to change in,

app/code/local/VP/CartOverride/Model/Observer.php

<?php

class VP_CartOverride_Model_Observer

{

            public function checkCart(Varien_Event_Observer $observer)

            {

                //Mage::dispatchEvent('admin_session_user_login_success', array('user'=>$user));

                //$user = $observer->getEvent()->getUser();

                //$user->doSomething();

            }

}