Magento 2.1 : How to extend Product listing in your custom product list and apply SKU Filter

Question

I have a Custom module which have customer mapped with certain products , I want to show a custom listing of those products with layered navigation

After Extending product list block in my custom block and changing

public function getLoadedProductCollection()
    {
             return $this->_getProductCollection()->addAttributeToFilter('sku',array('nin'=> $this->getSku()));
    }

On list.phtml

$_productCollection = $block->getLoadedProductCollection();
print_r($_productCollection->getData());
echo"</pre>";

give a Filter collection, But when i Iterate it with

foreach ($_productCollectionTest as $_productTest) {
    echo"<pre>";
    print_r($_productTest->getData());
    echo"</pre>";
}

I get a unfiltered Result

Answer 1

You added the filter after the collection was already loaded.

Then in your test code, you fell into the "collection->getData()" trap, that i explained in How to correctly select the first item from a filtered collection?

This results in a second database query as soon as you call getData() and this time, your new filter is applied. But it does not change the _items property, so your previously loaded result is still used for everything else.

By the way, I still did not come across any reasonable use case for this method. It's used internally by load() but probably should not have been public. The core doesn't use it from outside the collection class anywhere as far as I see.

Solution

Clear the collection (which resets _items and marks it as not loaded):

public function getLoadedProductCollection()
{
    $collection = $this->_getProductCollection();
    $collection->clear();
    $collection->addAttributeToFilter('sku',array('nin'=> $this->getSku()));
    return $collection;
}