async void addOffer_Clicked(object sender, EventArgs e) { string title = titleEntry.Text; string description = descriptionEntry.Text; int categoryId = Convert.ToInt32(((Category)CategoryBinder.SelectedItem).CategoryID); int quantity = Convert.ToInt32(quantityEntry.Text); string price = priceEntry.Text; OfferState state = (OfferState)StateBinder.SelectedItem; var offerItem = new Models.BindingModels.OfferBindingModel { Title = title, Description = description, CategoryID = categoryId, InStockOriginaly = quantity, Price = price, UserID = Session.user.UserID, OfferState = state }; if (string.IsNullOrEmpty(titleEntry.Text) || string.IsNullOrEmpty(descriptionEntry.Text)) { await DisplayAlert("Enter data", "Enter valid data", "Ok"); } else { try { OfferItem response = await AddOfferViewModel.AddOfferAsync(offerItem); if (response != null) { output.Text = "Oferta dodana pomyślnie!"; } else { } } catch (AggregateException err) { foreach (var errInner in err.InnerExceptions) { Debug.WriteLine(errInner); //this will call ToString() on the inner execption and get you message, stacktrace and you could perhaps drill down further into the inner exception of it if necessary } ; } } }