private async void nextButtonclicked(object sender, EventArgs e) { if (fullName.Text.Length == 0) { await DisplayAlert("Warning", "Full name field empty.", "OK"); return; } else if (company.Text.Length == 0) { await DisplayAlert("Warning", "Company field empty.", "OK"); return; } else if (email.Text.Length == 0) { await DisplayAlert("Warning", "E-mail field empty.", "OK"); return; } else if (telno.Text.Length == 0) { await DisplayAlert("Warning", "Telephone number field empty.", "OK"); return; } if (checkbox.IsChecked) { viewmodel.saveUserData(fullName.Text, company.Text, email.Text, telno.Text, country.Text); } else { viewmodel.clearUserData(); } await Navigation.PushAsync(new EnquiryMessagePage(fullName.Text, company.Text, email.Text, telno.Text, country.Text, viewmodel)); }