public function GetList($pageNumber, $pageSize, $sortField = null, $sortDirection = null, $filter = null)
 {
     $user = $this->repo->LoadById($this->user->UserId);
     if (!$user->IsInRole(RoleLevel::SCHEDULE_ADMIN)) {
         return new PageableData();
     }
     $ids = array();
     $filter = new SqlFilterNull();
     foreach ($user->Groups() as $group) {
         if ($group->IsScheduleAdmin) {
             $ids[] = $group->GroupId;
         }
     }
     $filter->_And(new SqlFilterIn(new SqlFilterColumn(TableNames::SCHEDULES_ALIAS, ColumnNames::RESOURCE_ADMIN_GROUP_ID), $ids));
     return parent::GetList($pageNumber, $pageSize, $sortField, $sortDirection, $filter);
 }