private void onSignUp() { user.Username = username; user.Password = password; if (!string.IsNullOrEmpty(user.Username) && !string.IsNullOrEmpty(user.Password)) { _validateUserService.userSignIn(user); App.Current.MainPage.DisplayAlert("User added", "You can log in", "Ok"); _navigation.NavigateAsync(nameof(LoginView)); } else { App.Current.MainPage.DisplayAlert("Error", "Fill in all fields", "Ok"); } }