private void button1_Click(object sender, EventArgs e) { DBL.User user = new DBL.User(); user.Username1 = textBoxUsername.Text; user.Password1 = textBoxPassword.Text; if (user.IsValidUser(user)) { notificationUser(textBoxUsername.Text); manage c = new manage(textBoxUsername.Text); c.Show(); this.Hide(); } else { //MessageBox.Show("Your username and password are not matched !"); textBoxPassword.Text = ""; textBoxUsername.Select(); textBoxUsername.SelectAll(); labelAlert.Text = "Your username and password are not matched !"; notificationUserFailed(); } }