private void buttonLogin_Click(object sender, EventArgs e) { CONNECT conn = new CONNECT(); DataTable table = new DataTable(); MySqlDataAdapter adapter = new MySqlDataAdapter(); MySqlCommand command = new MySqlCommand(); String query = "SELECT * FROM `users` WHERE `username`=@usn AND `password`=@pass"; command.CommandText = query; command.Connection = conn.getConnection(); command.Parameters.Add("@usn", MySqlDbType.VarChar).Value = textBoxUsername.Text; command.Parameters.Add("@pass", MySqlDbType.VarChar).Value = textBoxPassword.Text; adapter.SelectCommand = command; adapter.Fill(table); // kondisi pada login if (table.Rows.Count > 0) { // tampilkan main form this.Hide(); MainForm mForm = new MainForm(); mForm.Show(); ManageReservationForm manresForm = new ManageReservationForm(); manresForm.Show(); } else { // if (textBoxUsername.Text.Trim().Equals("")) { MessageBox.Show("Enter Your Username to Login", "Empty Username", MessageBoxButtons.OK, MessageBoxIcon.Error); } else if (textBoxPassword.Text.Trim().Equals("")) { MessageBox.Show("Enter Your Password to Login", "Empty Password", MessageBoxButtons.OK, MessageBoxIcon.Error); } else { MessageBox.Show("This Username or Password Doesn't Exists", "Wrong Data", MessageBoxButtons.OK, MessageBoxIcon.Error); } } }