private void HandleDateChanged(WorkViewModel task, DateTime oldDate, DateTime newDate)
        {
            //Filter and update oldDate and newDate Days (if available);
            var affectedDays = Days.Where(x => x.Date.Equals(oldDate) || x.Date.Equals(newDate));

            foreach (var affectedDay in affectedDays)
            {
                affectedDay.UpdateWorks(_works.Where(x => x.Date.Equals(affectedDay.Date)));
                affectedDay.Date = affectedDay.Date;
            }
            RaisePropertyChanged(() => SumHours);
            RaisePropertyChanged(() => IsValidSumHours);
            RaisePropertyChanged(() => Header);
        }
 private void HandleHoursChanged(WorkViewModel obj)
 {
     RaisePropertyChanged(() => SumHours);
     RaisePropertyChanged(() => IsValidSumHours);
 }