async void OnLoginButtonClicked(object sender, EventArgs e) { var user = new User { Email = emailEntry.Text, Password = passwordEntry.Text }; userDB = new UserDatabase(); if (userDB.AreCredentialsValid(user)) { Navigation.InsertPageBefore(new HomePageCS(), this); await Navigation.PopAsync(); } else { messageLabel.Text = "Login failed"; passwordEntry.Text = string.Empty; } }