private void OnNewAddAdress(MedicalPractice obj) { if (Model == null) { return; } IsEditingAddress = false; SelectedAddress = new MedicalPracticeAddress(); SelectedAddress.State = AvailableStates.Select(state => state).FirstOrDefault(); SelectedAddress.PropertyChanged += (o, e) => SelectedAddress.Validate(); ShowAddressPopup = Visibility.Visible; }