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.

• 7ochem: The block holds the collection, so you could also call $block->getCollection() in the observer, right?
• chris: Thanks for you response. I just have a few questions: 1. where does $resource come from ? I don't have this variable in the Grid.php 2. you talk about the alias to get the database ? is it the database name or should I use something else ? And you're right, the udropship_vendor used in my custom column is a product's attribute.
• laketuna: @7ochem, I extend _prepareCollection when I modify grids because you can do everything in one rewrite. I have used other approaches in modifying grids (observer, XML update, etc.) but I find the block rewrite to be the best.
• laketuna: @christophe, updated the ansnwer.
• chris: This works now, I'll continue to look for information about database manipulation with Magento though. Thank you.