// checks for an existing user before processing sign in private void AttemptSignIn(string username, string password) { if (signInService.UsernameExists(username)) { if (signInService.ProcessSignIn(username, password)) { Main main = new Main(username); main.Show(); this.Dispose(); } else { OutcomeMsg.Text = " Error! Entered password was incorrect!"; } } else { OutcomeMsg.Text = "Error! No such user exists"; } }