//save button clicked async void SavleClicked(object sender, System.EventArgs e) { if (configurationModel.synchronization && string.IsNullOrEmpty(configurationModel.duration)) { await DisplayAlert(ResourcesValues.AppName, ResourcesValues.FillDurationMessage, ResourcesValues.OkMessage); } else { await appServices.SaveConfiguration(configurationModel); await Navigation.PopModalAsync(false); } }