Add Post Parent Field

/**

 * Register a Post Parent field for campaigns.

 *

 * This will allow the campaign post parent to be edited in the

 * campaign management page in the WordPress dashboard.

 */

function ed_charitable_register_campaign_post_parent_field() {

    $campaigns = get_posts( array(

        'post_type'      => Charitable::CAMPAIGN_POST_TYPE,

        'post_status'    => 'publish',

        'posts_per_page' => -1,

        'fields'         => 'ids',

    ) );

    $options = array(

        0 => 'No Parent',

    );

    $options = $options + array_combine(

        $campaigns,

        array_map( 'get_the_title', $campaigns )

    );

    $field = new Charitable_Campaign_Field( 'post_parent', array(

        'label'          => 'Post Parent',

        'data_type'      => 'core',

        'value_callback' => 'charitable_get_campaign_post_field',

        'admin_form'     => array(

            'priority' => 1,

            'type'     => 'select',

            'options'  => $options,

        )

    ));

    charitable()->campaign_fields()->register_field( $field );

}

add_action( 'init', 'ed_charitable_register_campaign_post_parent_field' );