public MyIncidentsViewModel() { Title = "Mes incidents"; Incidents = new ObservableCollection <Incident>(); LoadIncidentsCommand = new Command(async() => await ExecuteLoadIncidentsCommand()); MessagingCenter.Subscribe <NewIncidentPage, Incident>(this, "AddIncident", async(obj, incident) => { var _incident = incident as Incident; Incidents.Add(_incident); await DataStore.AddIncidentAsync(_incident); }); }