silverstripe-framework/docs/en/02_Developer_Guides/15_Customising_the_Admin_Interface/How_Tos/Extending_An_Existing_ModelAdmin.md

title	summary
Extending an existing ModelAdmin	ModelAdmin interfaces that come with the core can be customised easily

Extending existing ModelAdmin

Sometimes you'll work with ModelAdmins from other modules. To customise these interfaces, you can always subclass. But there's also another tool at your disposal: The Extension API.

use SilverStripe\Core\Extension;

class MyAdminExtension extends Extension 
{
    // ...
    public function updateEditForm(&$form) 
    {
        $form->Fields()->push(/* ... */)
    }
}

Now enable this extension through your [config.yml](/topics/configuration) file.

MyAdmin:
  extensions:
    - MyAdminExtension

The following extension points are available: updateEditForm(), updateSearchContext(), updateSearchForm(), updateList(), updateImportForm.