Filter collection with attribute from custom module

Question

I have a custom module which I load data with following code inside list.phtml:

foreach ($_productCollection as $_product){
$_id = $_product->getId();
$event = Mage::getModel('aw_eventbooking/event');
$event = $event->loadByProductId($_id);
$eventStartDate = $event->getEventStartDate();
}

I want to create a way to filter products based on event start date, I modified List.php on Mage_Catalog_Block_Product_List to do something like this:

$now = new DateTime();
$now = $now->format('Y-m-d H:i:s');
$strnow = strtotime($now);

$this->_productCollection = $layer->getProductCollection();
$this->_productCollection
            ->getSelect()
            ->where('ATTRIBUTE START DATE > $now');
}

The problem is, how can I get the "ATTRIBUTE START DATE", the $event->getEventStartDate(); to make the filter possible? Please help, I am new to magento

I want something like this:

$eventcollection=$this->getLoadedProductCollection();
    $eventcollection = $eventcollection
    ->getSelect()
    ->where('$event->getEventStartDate() > $strnow');

Is this somehow possible?

Answer 1

$now = new DateTime();
$now = $now->format('Y-m-d H:i:s');
$strnow = strtotime($now);

$this->_productCollection = $layer->getProductCollection();
$products = $this->_productCollection
->addAttributeToSort('created_at', 'desc')
->addAttributeToFilter('created_at', array('gteq' =>$now));

I do not quite understand where(**'ATTRIBUTE START DATE > $ now'**); , but I hope that I will push you to the right decision.

I assume that this attribute is a product creation 'ATTRIBUTE START DATE'.

More information on the filters you can see here addFilter vs addFieldToFilter