public ExamViewModel(IEventAggregator eventAggregator) { this.eventAggregator = eventAggregator; Exams = new ObservableCollection <Exam>(ServiceDataProvider.GetAllExams()); ServiceDataProvider.AddExamNotification += ServiceDataProvider_AddExamNotification; eventAggregator.GetEvent <ExamPeriodEvent>().Subscribe(p => SubcribeToParentTableNameChange(p)); eventAggregator.GetEvent <CourseEvent>().Subscribe(p => SubcribeToParentTableNameChange(p)); }