public bool SuaDoiThongTinHoaDon(ThuPhi tp)
        {
            string sql = string.Format("Update HOADON set MaDichVu = '{0}', ThanhTien = '{1}', NgayLap = '{2}' "
                + " where MaHoaDon = '{3}'", tp.MaDichVu, tp.ThanhTien, tp.Ngaylap.ToString("MM/dd/yyyy"), tp.MaHoaDon);

            if (connData.ExcuteQuery(sql))
                return true;
            return false;
        }
        public bool LuuThongTinHoaDon(ThuPhi tp)
        {
            string sql = string.Format("Insert Into HOADON(STT, MaHoaDon, MaNhanVien, MaBenhAn, NgayLap, ThanhTien, MaDichVu)"
                + " Values('{0}', '{1}', '{2}', '{3}', N'{4}', '{5}', '{6}')", "0", tp.MaHoaDon, tp.MaNhanVien, tp.MaBenhAn,
                tp.Ngaylap.ToString("MM/dd/yyyy"), tp.ThanhTien, tp.MaDichVu);

            if (connData.ExcuteQuery(sql))
                return true;
            return false;
        }
        private ThuPhi LayThongTinThuPhi()
        {
            ThuPhi tp = new ThuPhi();

            tp.MaHoaDon = txtMaPhieuThu.Text;
            tp.MaBenhAn = txtMaBenhAn.Text;
            tp.MaDichVu = cboTenDichVu.SelectedValue.ToString();
            tp.MaNhanVien = txtMaNhanVien.Text;
            tp.Ngaylap = Convert.ToDateTime(dtPickerNgayThu.Value.ToString());
            tp.ThanhTien = Convert.ToInt64(txtDonGia.Text);

            return tp;
        }