如何将自定义数据添加到已加载的Magento集合

Question

I've been working on merging two different collections together and I'm finding it very hard to do.

Actually, the only thing I'm trying to do is adding another property to an already instantiated (I think) collection.

This is my code:

private function _addProductsToBanners()
{
    $skus = $this->_getBannersSkus();

    $products = Mage::getResourceModel('catalog/product_collection')
        ->addFieldToFilter('sku', array('in' => $skus))
        ->addAttributeToSelect(array('name'));

    /** @var Developer_Banners_Model_Resource_Banner_Collection $banners */
    $banners = $this->banners;

    foreach ($banners as $banner) {
        foreach ($products as $product) {
            if ($banner->getSku() == $product->getSku())
            {
                $banner->setData('product', 1);
            }
        }
    }
    echo '<pre>';
    print_r($banners->getData());
    echo '</pre>';
}

The problem here is, that when printing the $banners collection with getData() I can't see the [product] property, but if I do it without getData() then I see it.

If you have any ideas I would greatly appreciate it!

Thanks!

Answer 1

When Developer_Banners_Model_Resource_Banner_Collection inherits from Mage_Core_Model_Resource_Db_Collection_Abstract and you add an item, the item is not added to the $_data property but to the $_items property.

protected function _addItem($item)
{
   $this->_items[] = $item;
   return $this;
}

When you call then the getData() method, the $_data property is still null. The getData() method will then fetch the data from the DB and return the result.

public function getData()
{
    if ($this->_data === null) {


        $this->_renderFilters()
             ->_renderOrders()
             ->_renderLimit();
        /**
         * Prepare select for execute
         * @var string $query
         */
        $query       = $this->_prepareSelect($this->getSelect());
        $this->_data = $this->_fetchAll($query, $this->_bindParams);
        $this->_afterLoadData();
    }
    return $this->_data;
}

By just iterating on the object the each() method is executed:

public function each($obj_method, $args=array())
    {
        foreach ($args->_items as $k => $item) {
            $args->_items[$k] = call_user_func($obj_method, $item);
        }
    }

This method uses the $_items property as data source. Unfortunately I can't explain this behaviour right now.

Answer 2

我发现的是，直到您实际调用getData() ，才设置集合_data属性，但是实际上设置了每个集合成员上的_data ，因此可以在迭代集合时访问新添加的属性。