Magento : Get data from Varien_Data_Collection - php

Question

Hiho everybody! I hope you'll give me a clue about this because I'm still noob with Magento.
I try to display a list of products I get in an array. In Mage/Catalog/Block/Product/List.php, I created a new Varien_Data_Collection() in which I pushed my products objects (with ->addItem($product)).
Then I return my custom collection and List.php class does his work with it to display the list of products.
When I call the page in my browser, I had the right number of displayed products and when I click on it to see the product page, I get the right page.
However, all the data (like the product name, the price, etc) are empty. I guess that the methods used by List class to catch these data fail with my Varien_Data_Collection object.
To illustrate, here is my code sample :
// getting a particular product
$mainProduct = Mage::getModel('catalog/category')->load($currentCat->getId());
$mainProduct = $mainProduct->getProductCollection();
$mainProduct = $mainProduct->addAttributeToFilter('product_id', $_GET['cat_id']);
// creating a custom collection
$myCollection = new Varien_Data_Collection();
foreach ($mainProduct as $product) {
// getting my particular product's related products in an array
$related = $product->getRelatedProductIds();
if ($this->array_contains($related, $_GET['cat_id'])) {
// if it suits me, add it in my custom collection
$myCollection->addItem($product);
}
}
return $myCollection;
And this is what I get in my list page :
When I var_dump($myCollection), I can see that ['name'], ['price'], etc fields are not referenced. Only ['product_id'] and many other fields I don't care about.
My very ultimate question is : how can I return a collection containing these products data to my List class ? I know that it is poorly explained but my English is very limited and I try to do my best :(

Answer 1

Calling ->getProductCollection() against a category only returns skeleton data for each product in the created collection. If you want full data for each of the products, you need to then load them, so in your foreach loop you would have:
$product = Mage::getModel('catalog/product')->load($product->getId());
However the way in which you are building the collection is not the best working practice - you should never have to create your own Varien_Data_Collection object, instead you should be creating a product collection as follows:
$collection = Mage::getModel('catalog/product')->getCollection();
Then before you load the collecion (which the foreach loop or calling ->load() against the collection will do as 2 examples), you can filter the collection according to your requirements. You can either do this using native Magento methods, one of which you are already using (addAttributeToFilter()) or I prefer to pull the select object from the collection and apply filtering this way:
$select = $collection->getSelect();
You can then run all of the Zend_Db_Select class methods against this select object to filter the collection.
http://framework.zend.com/manual/1.12/en/zend.db.select.html
When the collection has been loaded, the products inside it will then contain full product data.

Answer 2

first of all pelase do not use $_GET variable, use Mage::app()->getRequest()->getParams();
second why not try to build your collection correctly from the start?
here is what your code does:
$mainProduct = Mage::getModel('catalog/category')->load($currentCat->getId());
$mainProduct = $mainProduct->getProductCollection();
$mainProduct = $mainProduct->addAttributeToFilter('product_id', $_GET['cat_id']);
get one product, I mean you load a category then load a product collection, then filter by product id.. why not:
$mainProduct = Mage::getModel('catalog/product')->load($yourSearchedId);
I aslo do not see why you filter products by $_GET['cat_id'] which looks like a category id...
To conclude you can get more help if you explain exactly what you are trying to find. It looks like you are trying to find all products that have a given product as related. So why not set for that given product the related product correctly and get the related products collection.
$_product->getRelatedProductCollection();
UPDATE:
now that you cleared your request try this:
$relatedIds = $product->getRelatedProductIds();
$myCollection = Mage::getModel('catalog/category')
->load($currentCat->getId())
->getProductCollection();
$myCollection->addAttributeToFilter('product_id', array("in",$relatedIds));
//also addAttributeToSelect all attributes you may need like name etc
$myCollection->load(); //maybe you don't actualy need to load here
Please bear in mind I did not test this code it was written from teh top of my head, test it. But I hope you got the idea.