Correct usage of addAttributeToFilter in Magento

Question

I'm having issues filtering a product collection with a customer attribute using 'addAttributeToFilter.' I have a dropdown menu attribute with the options 'yes' and 'no' and I'd like to to show only a list of products with the attribute set to 'yes.' I'm currently using:

public function getReleasesCollection() {
$products = Mage::getModel('catalog/product')->getCollection() ->addAttributeToFilter('preorder', array ('eq' => 1)) ->addAttributeToSelect('name') ->addAttributeToSelect('releasedate');

However this does not return any products.

I have also tried using:

->addAttributeToFilter('manufacturer', 1);

->addAttributeToFilter('manufacturer', '1');

->addAttributeToFilter('manufacturer', 'Yes);

->addAttributeToFilter('manufacturer', array('eq' => '1'));

->addAttributeToFilter('manufacturer', array('eq' => 'Yes'));

I am able to filter by any other attribute such as name, sku, description, etc. but I'm unable to filter with my custom attribute.

Any pointers?

Answer 1

<?php 

class LSC_ReleaseCalendar_Block_Calendar extends Mage_Core_Block_Template 
{    
    public function getReleasesCollection()
  { 
        $preorderAttribute = 'preorder';
        $preorderValue = 'yes';
        $products = Mage::getModel('catalog/product')->getCollection()  
            ->addAttributeToSelect('*')
            ->addFieldToFilter(
                $preorderAttribute,
                    array(
                        'eq' => Mage::getResourceModel('catalog/product')
                            ->getAttribute($preorderAttribute)
                            ->getSource()
                            ->getOptionId($preorderValue)
                )
            );
        foreach ($products as $product) {
            echo $product->getName();
            echo $product->getReleaseDate();
        }
    }

}

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