Overview

The user field allows you to select one or multiple users. This field has several settings that can be displayed as a: simple select dropdown, checkbox list, or beautiful select dropdown with select2 library.

Screenshots

Beautiful select with select2 library (default):

Checkbox list:

Radio list:

Radio list inline:

Settings

Besides the common settings, this field has the following specific settings:

This field inherits the look and field (and settings) from other fields, depending on the field_type, which accepts the following value:

Note that for checkbox_list, the multiple setting is always set to true.

Sample code

This code shows users in select2 dropdown:

array(
    'name'        => 'User',
    'id'          => 'user',
    'type'        => 'user',

    // 'clone'    => true,

    // Field type.
    'field_type'  => 'select_advanced',

    // Placeholder.
    'placeholder' => 'Select an author',

    // Query arguments (optional). No settings means get all published users.
    // @see https://codex.wordpress.org/Function_Reference/get_users
    'query_args'  => array(),
),

The code below shows users in a radio list format:

array(
    'name'        => 'User',
    'id'          => 'user',
    'type'        => 'user',

    // 'clone'    => true,

    // Field type.
    'field_type'  => 'radio_list',

    // Inline radios? Inheritted from radio field.
    'inline'      => true,

    // Query arguments (optional). No settings means get all published users.
    // @see https://codex.wordpress.org/Function_Reference/get_users
    'query_args'  => array(),
),

Data

This field saves user ID(s) in the database.

If field is not multiple, then a single user ID is saved in the database. Otherwise, the field saves multiple user IDs in the database, where each user ID is store in a single row in the database with the same meta key (similar to what add_post_meta does with last parameter false).

If the field is cloneable, then the value is stored as a serialized array in a single row in the database.

Template usage

If field is not multiple, getting value is simple:

$user_id = rwmb_meta( $field_id );
$user = get_userdata( $user_id );
echo 'Username: ', $user->user_login;
echo 'User display name: ', $user->display_name;

If field is multiple, you can loop through the returned values like this:

$user_ids = rwmb_meta( $field_id );
foreach ( $user_ids as $user_id ) {
    $user = get_userdata( $user_id );
    echo '<p>', $user->display_name, '</p>';
}

If you just want to output selected users in an unordered list, use this code:

rwmb_the_value( $field_id );

Read more about rwmb_meta() and rwmb_the_value().