public void Save() { //TODO save Changes foreach (var userDocument in docs) { var doc = SelectedUser.UserDocuments.FirstOrDefault(d => d.Document == userDocument.Document); if (doc != null) { doc.IsAvailable = userDocument.IsAvailable; } else if (userDocument.IsAvailable) { SelectedUser.UserDocuments.Add(userDocument); } } Membership.AddOrUpdate(SelectedUser); SaveChanges(); IsModalVisible = false; RefreshItemSource(); }