public AttendanceManualViewModel() { attendanceManager = new AttendanceManager(); attendanceManager.AttendanceFixed += AttendanceManager_AttendanceFixed; attendanceManager.SubscriptionClosed += AttendanceManager_SubscriptionClosed; messager = new Messager(); AttendancePrice = 30; Groups = attendanceManager.GetGroups(); if (Groups.Count > 0) { SelectedGroup = Groups[0]; } SelectedDate = DateTime.Today; }