据我所知，您所能做的就是通过pre_user_display_name 并检查它是否已经存在。不幸地WP_User_Query 不支持按查询display_name, 因此，我们还必须添加到WHERE 第via条pre_user_query. 此外，我想不出什么优雅的方法来处理display_name 除了不返回任何内容之外，已经存在，因为我们不知道通过过滤器这个潜在的显示名称附加到哪个用户。也许我只是累了，错过了一些显而易见的事情！总之，我创建了一个快速测试：

class wpa82239_display_name {
    private $display_name;

    public function __construct(){
        add_filter( \'pre_user_display_name\', array( $this, \'display_name_filter\' ) );
    }

    public function display_name_filter( $display_name ){

        $this->display_name = $display_name;
        add_action( \'pre_user_query\', array( $this, \'user_query_filter\' ) );
        $args = array(
            \'number\' => 1,
            \'fields\' => \'ID\'
        );
        $user_search = new WP_User_Query( $args );
        remove_action( \'pre_user_query\', array( $this, \'user_query_filter\' ) );

        if( 0 == $user_search->total_users )
            return $display_name;

        return null;
    }

    public function user_query_filter( $query ){
        global $wpdb;
        $query->query_where .= $wpdb->prepare(
            " AND $wpdb->users.display_name = %s",
            $this->display_name
        );
    }

}
$wpa82239_display_name = new wpa82239_display_name();

它很脏，但确实有用，只需将它放在主题函数中即可。php在单个站点上，或在函数中。多站点上mu插件文件夹中的php文件。

该脚本还将扫描现有用户（如果您的站点已经有许多用户），任何非唯一的显示名称都将更新并替换为用户名。

我知道这并不完全理想，但任何关于处理现有用户或改进的建议都是受欢迎的。

 
    // Make nickname & display_name unique
    // and automatically change non unique nicks & display name to username
    // in case you already have existing users
    // by Ashok & Vaughan Montgomery
    /*
     * adding action when user profile is updated
     */
    add_action(\'personal_options_update\', \'check_display_name\');
    add_action(\'edit_user_profile_update\', \'check_display_name\');
    function check_display_name($user_id) {
            global $wpdb;
        // Getting user data and user meta data
            $err[\'display\'] = $wpdb->get_var($wpdb->prepare("SELECT COUNT(ID) FROM $wpdb->users WHERE display_name = %s AND ID <> %d", $_POST[\'display_name\'], $_POST[\'user_id\']));
        $err[\'nick\'] = $wpdb->get_var($wpdb->prepare("SELECT COUNT(ID) FROM $wpdb->users as users, $wpdb->usermeta as meta WHERE users.ID = meta.user_id AND meta.meta_key = \'nickname\' AND meta.meta_value = %s AND users.ID <> %d", $_POST[\'nickname\'], $_POST[\'user_id\']));
        foreach($err as $key => $e) {
            // If display name or nickname already exists
            if($e >= 1) {
                $err[$key] = $_POST[\'username\'];
                // Adding filter to corresponding error
                add_filter(\'user_profile_update_errors\', "check_{$key}_field", 10, 3);
            }
        }
    }
    /*
     * Filter function for display name error
     */
    function check_display_field($errors, $update, $user) {
            $errors->add(\'display_name_error\',(\'Sorry, Display Name is already in use. It needs to be unique.\'));
            return false;
    }
    /*
     * Filter function for nickname error
     */
    function check_nick_field($errors, $update, $user) {
            $errors->add(\'display_nick_error\',(\'Sorry, Nickname is already in use. It needs to be unique.\'));
            return false;
    }
    /*
     * Check for duplicate display name and nickname and replace with username
     */
    function display_name_and_nickname_duplicate_check() {
        global $wpdb;
        $query = $wpdb->get_results("SELECT * FROM $wpdb->users");
        $query2 = $wpdb->get_results("SELECT * FROM $wpdb->users as users, $wpdb->usermeta as meta WHERE users.ID = meta.user_id AND meta.meta_key = \'nickname\'");
        $c = count($query);
        for($i = 0; $i < $c; $i++) {
            for($j = $i+1; $j < $c; $j++) {
                if($query[$i]->display_name == $query[$j]->display_name){
                    wp_update_user(
                            array(
                                  \'ID\' => $query[$i]->ID,
                                  \'display_name\' => $query[$i]->user_login
                            )
                        );
                }
                if($query2[$i]->meta_value == $query2[$j]->meta_value){
                    update_user_meta($query2[$i]->ID, \'nickname\', $query2[$i]->user_login, $prev_value);
                }
            }
        }
    }
    // Call the function
    display_name_and_nickname_duplicate_check();


/*
 * Calling the display_name_and_nickname_duplicate_check() again when a new user is registered
 */
add_action( \'user_register\', \'check_nickname\', 10, 1 );
function check_nickname() {
    display_name_and_nickname_duplicate_check();
}