public void Load(PeriodDTO period)
 {
     ShowBusyIndicator("در حال دریافت اطلاعات...");
     Period      = period;
     DisplayName = PeriodMgtAppLocalizedResources.JobPositionInPeriodTreeViewTitle + " " + Period.Name;
     jobPositionInPeriodService.GetJobPositionsWithActions(
         (res, exp) => appController.BeginInvokeOnDispatcher(() =>
     {
         if (exp == null)
         {
             JobPositionInPeriodTree = SilverLightTreeViewHelper <JobPositionInPeriodDTOWithActions> .prepareListForTreeView(res);
             HideBusyIndicator();
         }
         else
         {
             HideBusyIndicator();
             appController.HandleException(exp);
         }
     }), period.Id);
 }