How to Fetch / Add a Custom Column in Product List Grid In Admin

Question

I've created a new module in order to add a column to the product list displayed in the admin section of Magento. The column is displaying an ID and I want it to display the name (from another table) belonging to that ID.

app/code/local/Mypackage/Customgrid/etc/Config.xml

<?xml version="1.0"?>
<config>
    <modules>
        <Mypackage_Customgrid>
            <version>0.4.0</version>
        </Mypackage_Customgrid>
    </modules>

    <global>
        <models>
            <mypackage_customgrid>
                <class>Mypackage_Customgrid_Model</class>
            </mypackage_customgrid>
        </models>
    </global>

    <adminhtml>
        <events>
            <core_block_abstract_prepare_layout_before>
                <observers>
                    <customgrid_column_append>
                        <type>model</type>
                        <class>Mypackage_Customgrid_Model_Observer</class>
                        <method>appendCustomColumn</method>
                    </customgrid_column_append>
                </observers>
            </core_block_abstract_prepare_layout_before>
        </events>
    </adminhtml>
</config>

app/code/local/Mypackage/Customgrid/Model/Observer.php

class Mypackage_Customgrid_Model_Observer extends Varien_Event_Observer {

    public function appendCustomColumn(Varien_Event_Observer $observer) {
        $block = $observer->getBlock();
        if (!isset($block)) {
            return $this;
        }

        if ($block->getType() == 'adminhtml/catalog_product_grid') {
            /* @var $block Mage_Adminhtml_Block_Customer_Grid */
            $block->addColumnAfter('udropship_vendor', array(
                'header'    => 'Vendor',
                'index'     => 'udropship_vendor',
                'type'  => 'text',
            ), 'visibility');
        }
    }
}

As you can see in the above code, I'm using the uDropship extension. The above code display the vendor ID related to each product, but I would like this column to display the vendor name related to each product.

I've tried to change the collection fetch in the file app/code/core/Adminhtml/Block/Catalog/Product/Grid.php (only for test purpose, I'll overwrite this file if I find how to do that). But I don't understand how to get the name value from the database.

Btw, the table schema in which the data I want to display is stored looks like something like that

table: magentoudropship_vendor
    vendor_id
    vendor_name
    [...]

Is anyone capable of guiding me through this ? Anything which can help me to understand how to manipulate the database is welcome.

Answer 1

app/code/core/Adminhtml/Block/Catalog/Product/Grid.php is the right place to start. What you need to do is rewrite Mage_Adminhtml_Block_Catalog_Product_Grid::_prepareCollection and join magentoudropship_vendor, so that you have access to the vendor_name for the grid. I'm assuming you have vendor_id as an attribute to the product (correct me if I'm wrong).

Additionally, I would add the column to the product list grid in this rewrite. See Mage_Adminhtml_Block_Catalog_Product_Grid::_prepareColumns. This is where you can add additional columns.

You need something like...

protected function _prepareCollection()
{
    $resource = Mage::getSingleton('core/resource');
    $collection = Mage::getModel('catalog/product')->getCollection()
        ->addAttributeToSelect('sku')
        ->addAttributeToSelect('name')
        ->addAttributeToSelect('attribute_set_id')
        ->addAttributeToSelect('type_id');

    $collection->getSelect()
        ->join(
            array('v' => $resource->getTableName('...')), // Insert approprirate alias to get `magentoudropship_vendor`
            'main_table.vendor_id = v.vendor_id',
            array('vendor_name')    // List of wanted columns from the custom table
        );
    ...
}

Alias for the getTableName() method is found in your config.xml of the uDropShip extension. e.g. model_alias/table_name. Copy and paste the <models>...<models> if you're still not sure.