private void UpdateVisibleActivitiesCount()
        {
            var dates = DateNavigator.GetSelectedDates();

            dates.ToList().Sort();

            if (dates.Count > 0 && ActiveCalendar != null)
            {
                if (dates[0].AddDays(dates.Count - 1).Day == dates[dates.Count - 1].Day)
                {
                    var start      = new DateTime(dates[0].Year, dates[0].Month, dates[0].Day, 0, 0, 0);
                    var end        = new DateTime(dates[dates.Count - 1].Year, dates[dates.Count - 1].Month, dates[dates.Count - 1].Day, 23, 59, 59);
                    var activities = DataManager.GetActivities(new ActivityQuery(ActivityTypes.All, new Infragistics.DateRange(start, end), ActiveCalendar)).Activities;
                    viewItemsCountChangedEvent.Publish(activities.Count);
                }
            }
        }
 void DateNavigator_SelectedDatesChanged(object sender, Infragistics.Controls.Editors.SelectedDatesChangedEventArgs e)
 {
     outlookDateNavigatorSelectedDatesChanged.Publish(new ObservableCollection <DateTime>(DateNavigator.GetSelectedDates()));
     UpdateVisibleActivitiesCount();
 }