private void button1_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); if (table.Rows.Count > 0) { //MessageBox.Show("YES"); this.Hide(); Main_Form mform = new Main_Form(); mform.Show(); } else { //MessageBox.Show("No"); 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("Incorrect password or username", "Wrong Data", MessageBoxButtons.OK, MessageBoxIcon.Error); } } }