private void buttonLogout_Submit_Click_1(object sender, EventArgs e) { DB db = new DB(); String username = textUsername.Text; String password = textPassword.Text; DataTable table = new DataTable(); MySqlDataAdapter adapter = new MySqlDataAdapter(); //Validation of the login input MySqlCommand command = new MySqlCommand("SELECT * FROM `user_data` WHERE `username` = @usn and `password` = @pass", db.getConnect()); command.Parameters.Add("@usn", MySqlDbType.VarChar).Value = username; command.Parameters.Add("@pass", MySqlDbType.VarChar).Value = password; adapter.SelectCommand = command; adapter.Fill(table); if (table.Rows.Count > 0) { MySqlCommand command2 = new MySqlCommand("SELECT * FROM `login_current` WHERE `username` = @username", db.getConnect()); command2.Parameters.Add("@username", MySqlDbType.VarChar).Value = username; command2.CommandType = CommandType.Text; command2.Connection = Connect; Connect.Open(); try { MySqlDataReader dr; dr = command2.ExecuteReader(); while (dr.Read()) { if ((string)dr["username"] == textUsername.Text) { id = (int)dr["id"]; student_no = (string)dr["student_no"]; name = (string)dr["name"]; course = (string)dr["course"]; address = (string)dr["address"]; phone_no = (int)dr["phone_no"]; break; } } dr.Close(); } catch (Exception ex) { MessageBox.Show(ex.Message); } Connect.Close(); MySqlCommand UpdateRecord = new MySqlCommand("UPDATE `records` SET `Logout_time`= CURRENT_TIMESTAMP WHERE `username` = '" + textUsername.Text + "' ORDER BY `Login_time` DESC LIMIT 1", db.getConnect()); try { db.openConnection(); if (UpdateRecord.ExecuteNonQuery() == 1) { MySqlCommand DeleteLogin_current = new MySqlCommand("DELETE FROM `login_current` WHERE `login_current`.`id` = " + id + "", db.getConnect()); try { db.openConnection(); if (DeleteLogin_current.ExecuteNonQuery() == 1) { MessageBox.Show("Logout Successful"); this.Hide(); Home Home = new Home(); Home.ShowDialog(); this.Close(); } else { MessageBox.Show("Logout Failed"); } db.closeConnection(); } catch (Exception ex) { MessageBox.Show(ex.Message); } } else { MessageBox.Show("Logout Failed"); } db.closeConnection(); } catch (Exception ex) { MessageBox.Show(ex.Message); } } else { MessageBox.Show("Please check your username or password", "Invalid Input"); } }