Still Show Added Product under Related Products after adding to cart in Magento

Question

Is anyone familiar with this. I have noticed that after I add a product to cart, it disappears in my list of related products. What I want is to still show that specific product even if I already added it to cart.

I think it's a default Magento feature that after adding an item to cart, it disappears under the related products of a specific product.

Can I do this easily via Magento admin? Or do I need to modify a core code or template file? I hope some Magento expert can guide me to the right direction. O_O

Answer 1

You need to rewrite the block Mage_Catalog_Block_Product_List_Related and from the method _prepareData remove this:

        Mage::getResourceSingleton('checkout/cart')->addExcludeProductFilter($this->_itemCollection,
            Mage::getSingleton('checkout/session')->getQuoteId()
        );