codice:
class xenD_Listener_xenDDay
{
	


	
 public static function includeMyDigestDay($hookName, &$contents, array $hookParams, XenForo_Template_Abstract $template)
    {


$db = XenForo_Application::getDb();
                       
                     


                        if ( !$db ) {


                            die( 'This script did not connect to the database' . mysql_error() );
                        }


    $thread_qry11 = "SELECT u.email,uf.field_value FROM xf_user as u JOIN xf_user_field_value as uf ON u.user_id = uf.user_id WHERE uf.field_value = '1' AND uf.filed_id = 'xDNewsletter'";
			
			                        $row11 = XenForo_Application::get('db')->fetchAll($thread_qry11);
			
			                        foreach ( $row11 AS $rows11 ) {
			                        	$mailuseremail = $rows11['email'];
			                        	
			                        	
			                        }


}


la funzione che mi hai passato nel link è questa :





codice:
public function __toString()
{
    try {
        return (string) $this->name;
    } catch (Exception $exception) {
        return '';
    }
}
Ovviamente tutto nella classe di riferimento.