How to use postbox_classes_screen_id_box_id filter in WordPress

Welcome to the detailed guide on the `postbox_classes_screen_id_box_id` filter hook in WordPress. Here, we’ll explore how to use this hook to filter the postbox classes for a specific screen and box ID combo. This hook is quite helpful if you’re looking to customize the classes applied to your postboxes in the WordPress admin panel.

postbox_classes_screen_id_box_id filter

Filters the postbox classes for a specific screen and box ID combo.

apply_filters( "postbox_classes_{$screen_id}_{$box_id}", string[] $classes )

Description

This filter hook filters the postbox classes for a specific screen and box ID combo. It consists of one parameter: `$classes`, an array of postbox classes. The dynamic portions of the hook name, `$screen_id` and `$box_id`, refer to the screen ID and meta box ID, respectively. This hook is used by `postbox_classes()` which returns the list of classes to be used by a meta box.

Parameters

• $classes: (string[]) An array of postbox classes.

Live Examples

Adding a New Class to Postbox

In this example, we add a new class to the array of postbox classes.

add_filter('postbox_classes_screen_id_box_id', 'weplugins_add_metabox_classes');

function weplugins_add_metabox_classes($classes) {
    array_push($classes, 'another_class');
    return $classes;
}

Removing a Hook Callback

This example demonstrates how to remove a hook callback to stop adding the new class to postbox classes.

// remove the filter 
remove_filter('postbox_classes_screen_id_box_id', 'weplugins_add_metabox_classes', 10);

Modifying Existing Classes

Here, we modify the existing classes by appending a suffix to each class name.

add_filter('postbox_classes_screen_id_box_id', 'weplugins_modify_metabox_classes');

function weplugins_modify_metabox_classes($classes) {
    foreach ($classes as &$class) {
        $class .= '_modified';
    }
    return $classes;
}