您可以使用“”检查现有用户username_exists“WordPress函数和插入用户使用”wp_insert_user“网络站点的功能如下：

if( username_exists( \'username\' ) ) {
    _e( \'Username already exists\', \'your-text-domain\' );
} else {
    _e( \'Username does not exists.\', \'your-text-domain\' );

    $userdata = array(
        \'user_login\'  =>  \'username\',
        \'user_url\'    =>  \'http://example.com\',
        \'user_pass\'   =>  wp_generate_password(),  
    );

    $user_id = wp_insert_user( $userdata ) ;

    //On success
    if( !is_wp_error($user_id) ) {
        _e( \'User created : \', \'your-text-domain\' ); echo $user_id;
    }

}

$blog_id = get_current_blog_id();
$user_id = username_exists( sanitize_text_field( $_POST[\'user_name\'] ) );

if ( $user_id && ! is_user_member_of_blog( $user_id, $blog_id ) ) {
    //Exist\'s but is not user of the current blog id
    $result = add_user_to_blog( $blog_id, $user_id, sanitize_text_field( $_POST[\'user_role\'] ) );
}