magento same product with many quantity different size change one time - magento

Question

I have a little experience in magento. All my products have custom size in option.
All products have different sizes and different prices.
Customer adds one product with quantity 5 to cart. So 5 products of this size are added to cart. When the customer adds another product with different size all products in cart change to this size.
How can i prevent this behavior?

Answer 1

Unless you're doing this programmatically (that is writing the code), there's no way to do this.
When Magento adds a product, it first looks into the quote / shopping cart to see if one already exists. If one does, it pulls that one and adds to the quantity. There is no way to turn this off.
Programmatically, you very manually add an item to a shopping cart. This is how...
$cart = Mage::getSingleton("checkout/cart");
foreach ($products_to_add as $product_id => $custom_options) {
$product = Mage::getModel("catalog/product")->load($product_id);
$options = new Varien_Object(array("options" => $custom_options,
"qty" => 1));
// some products may result in multiple products getting added to cart
// I beleive this pulls them all and sets the custom options accordingly
$add_all = $product->getTypeInstance(true)
->prepareForCartAdvanced($options, $product, Mage_Catalog_Model_Product_Type_Abstract::PROCESS_MODE_FULL);
foreach ($add_all as $add_me) {
$item = Mage::getModel('sales/quote_item');
$item->setStoreId(Mage::app()->getStore()->getId());
$item->setOptions($add_me->getCustomOptions())
->setProduct($add_me);
$item->setQty(1);
$cart->getQuote()->addItem($item);
}
}
// when done adding all the items, finally call save on the cart
$cart->save();