private void btnLuu_Click(object sender, EventArgs e) { SuDung.MaDV = cboDichVu.SelectedValue.ToString(); SuDung.MaHD = txtHoaDon.Text; SuDung.ThoiGian = DateTime.Now; DichVuDAO DichVuDAO = new DichVuDAO(); SuDung.Gia = DichVuDAO.GetGia(cboDichVu.SelectedValue.ToString()); DAL_SuDung.addSuDung(SuDung); dgvDanhSach.DataSource = DAL_SuDung.getDanhSach(); _them = false; btnLuu.Enabled = false; btnThem.Enabled = true; btnXoa.Enabled = true; timer1.Enabled = true; cboPhong.Enabled = false; cboDichVu.Enabled = false; }