public ListElevesVM() { _bm = BusinessLayer.BusinessManager.GetInstance(); _eleves = new ObservableCollection <DetailEtudiantVM>(); foreach (Eleve eleve in _bm.GetEleves()) { DetailEtudiantVM detailEtudiant = new DetailEtudiantVM { Nom = eleve.Nom, Prenom = eleve.Prenom }; ICollection <Note> notes = _bm.GetNotesByEleve(eleve.EleveId); detailEtudiant.Moyenne = 10; _eleves.Add(detailEtudiant); } if (_eleves != null && _eleves.Count > 0) { _detail = _eleves.ElementAt(0); } }