private void btnAdd_Click(object sender, EventArgs e)
        {
            AccountDao acDao = new AccountDao();

            if (txtEmployeeId.Text.Length > 0 && txtUsername.Text.Length > 0)
            {
                acDao.AddAccount(new Account(txtUsername.Text, txtUsername.Text, cboRole.SelectedIndex + 1, Convert.ToInt32(txtEmployeeId.Text)));
                LoadTable();
            }
        }