private void login_Click(object sender, EventArgs e)
    {
        try
        {
            string myConnection = "datasource = localhost;port=3306;username=root;password=";
            MySqlConnection myConn = new MySqlConnection(myConnection);
            MySqlCommand SelectCommand = new MySqlCommand("select username, password from library_sys.tbl_users where username = '" + this.txtusername.Text + "' and password = '" + this.txtpword.Text + "';", myConn);
            MySqlDataReader myReader;
            myConn.Open();
            myReader = SelectCommand.ExecuteReader();
            int count = 0;

            while (myReader.Read())
            {
                count = count + 1;
            }
            if (count == 1)
            {
                MessageBox.Show("Welcome to the LIBRARY MANAGEMENT SYSTEM!");
                this.Hide();
                Librarian lib = new Librarian();
                lib.Show();
            }
            else
            {
                MessageBox.Show("Invalid username or password.");
                myConn.Close();
            }
            myConn.Close();
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.Message);
        }