public ListeEleveViewModel() { _bm = BusinessLayer.BusinessManager.GetInstance(); _eleves = new ObservableCollection <DetailEleveViewModel>(); foreach (Eleve eleve in _bm.GetEleves()) { DetailEleveViewModel detailEleveViewModel = new DetailEleveViewModel { Nom = eleve.Nom, Prenom = eleve.Prenom, DateDeNaissance = eleve.DateNaissance, Notes = eleve.Notes, Absences = eleve.Absences }; //List<Note> notes = _bm.GetNotesByEleve(eleve.EleveId); //detailEleveViewModel.Moyenne = (int)notes.Select(n => n.LaNote).Average(); detailEleveViewModel.Moyenne = _bm.GetAverageByEleve(eleve.EleveId); _eleves.Add(detailEleveViewModel); } if (_eleves != null && _eleves.Count > 0) { _detail = _eleves.ElementAt(0); } }