In Magento, suppose we wanted to override/rewrite the core adminhtml block grid class which is originally based in app/code/core/Mage/Adminhtml/Block/Catalog/Product/Grid.php
To override a core adminhtml block grid, we need to do the following,
1. Create a new module named “AU_OverrideCatalogProduct”.
2. Create the global module config file in app/etc/modules/AU_OverrideCatalogProduct.xml with following content:
<?xml version="1.0"?> <config> <modules> <AU_OverrideCatalogProduct> <active>true</active> <codePool>local</codePool> </AU_OverrideCatalogProduct> </modules> </config>
3. Create the module in “local” code-pool. The illustration would be as follows:
app/code/local/AU/OverrideCatalogProduct/etc/config.xml
app/code/local/AU/OverrideCatalogProduct/Block/Adminhtml/Catalog/Product/Grid.php
4. In module config file, which is app/code/local/AU/OverrideCatalogProduct/etc/config.xml, add the following content
<?xml version="1.0" encoding="UTF-8"?> <config> <modules> <AU_OverrideCatalogProduct> <version>0.0.1</version> </AU_OverrideCatalogProduct> </modules> <global> <blocks> <au_overridecatalogproduct> <class>AU_OverrideCatalogProduct_Block</class> </au_overridecatalogproduct> <!-- Overriding adminhtml block --> <adminhtml> <rewrite> <catalog_product_grid>AU_OverrideCatalogProduct_Block_Adminhtml_Catalog_Product_Grid</catalog_product_grid> </rewrite> </adminhtml> </blocks> </global> </config>
5. Ensure that our newly created
AU/OverrideCatalogProduct/Block/Adminhtml/Catalog/Product/Grid.php
extends from Mage_Adminhtml_Block_ Catalog_Product_Grid like below:
class AU_OverrideCatalogProduct_Block_Adminhtml_Catalog_Product_Grid extends Mage_Adminhtml_Block_Catalog_Product_Grid { }
That’s all. If we do have cache enabled, to see the effect clear the cache and should be fine.