public CreateReportViewModel(IReportRepository repository)
 {
     StartDate = DateTime.Now;
     EndDate = DateTime.Now;
     view = new CreateReportView(){DataContext = this};
     db = repository;
     HeatSuppliers = new ObservableCollection<HeatSupplier>(repository.GetHeatSuppliers());
     DateTimeIntervals = new ObservableCollection<DateTimeInterval>(repository.GetDateTimeIntervals());
 }