public LoginViewModel( ILoginCredentialsViewModel credentials, ILogin2FaViewModel twoFactor, IDelegatingTwoFactorChallengeHandler twoFactorHandler) { twoFactorHandler.SetViewModel(twoFactor); Content = credentials; Done = credentials.Done; twoFactor.WhenAnyValue(x => x.TwoFactorType) .Subscribe(x => { Content = x == TwoFactorType.None ? (IDialogContentViewModel)credentials : twoFactor; }); }