private void submitButton_Click(object sender, EventArgs e) { String login = loginTextBox.Text; String password = passwordTextBox.Text; if (firstClickLogin || firstClickPassword || login == "" || password == "") { MessageBox.Show("Insert login and password before", "Autentication failed"); return; } byte answer = Connection.Authentication(login, password); String status = "Authentication has done successfully. Now you can log in."; String statusTitle = "Authentication done"; if (answer == Connection.AUTHENTICATION_FAILED_CODE) { status = "This login is used already or password is incorrect. Try again."; statusTitle = "Authentication failed"; } MessageBox.Show(status, statusTitle); if (answer == Connection.AUTHENTICATION_DONE_CODE) { this.Hide(); MessageForm messageForm = new MessageForm(login); messageForm.ShowDialog(); this.Close(); } }