public bool SuaDoiThongTinNhapVienBN(NhapVien nvi)
        {
            string sql = string.Format("Update NHAPVIEN set MaKhoa = '{0}', MaPhongBenh = '{1}', MaGiuongBenh = '{2}', "
            + "KetQuaChuanDoan = N'{3}', PhuongPhapDieuTri = N'{4}', NgayNhapVien = N'{5}', NgayXuatVienDK = N'{6}', TamUng = '{7}' where MaNhapVien = '{8}'",
            nvi.MaKhoa, nvi.MaPhongBenh, nvi.MaGiuongBenh, nvi.KetQuaChuanDoan, nvi.PhuongPhapDieuTri, nvi.NgayNhapVien.ToString("MM/dd/yyyy"),
            nvi.NgayXuatVienDK.ToString("MM/dd/yyyy"), nvi.TamUng, nvi.MaNhapVien);

            if (connData.ExcuteQuery(sql))
                return true;
            return false;
        }
        //ham luu thong tin nhap vien cua benh nhan
        public bool LuuThongTinNhapVienBN(NhapVien nvi)
        {
            string sql = string.Format("Insert into NHAPVIEN(STT, MaNhapVien, MaBenhAn, MaBenhNhan, MaKhoa, MaPhongBenh, "
            + " MaGiuongBenh, KetQuaChuanDoan, PhuongPhapDieuTri, NgayNhapVien, NgayXuatVienDK, TamUng) values ('{0}', '{1}',"
            +" '{2}', '{3}', '{4}', '{5}', '{6}', N'{7}', N'{8}', N'{9}', N'{10}', '{11}' )", "0", nvi.MaNhapVien,
            nvi.MaBenhAn, nvi.MaBenhNhan, nvi.MaKhoa, nvi.MaPhongBenh, nvi.MaGiuongBenh, nvi.KetQuaChuanDoan, nvi.PhuongPhapDieuTri,
            nvi.NgayNhapVien.ToString("MM/dd/yyyy"), nvi.NgayXuatVienDK.ToString("MM/dd/yyyy"), nvi.TamUng);

            if (connData.ExcuteQuery(sql))
                return true;
            return false;
        }
        //ham lay thong tin nhap vien
        private NhapVien LayThongTinNhapVien()
        {
            NhapVien nvi = new NhapVien();

            nvi.MaBenhNhan = txtNhapVien_MaBN.Text;
            nvi.MaBenhAn = txtNhapVien_MaBenhAn.Text;
            nvi.MaNhapVien = txtNhapVien_MaNhapVien.Text;
            nvi.KetQuaChuanDoan = txtNhapVien_KQChuanDoan.Text;
            nvi.MaKhoa = cboNhapVien_KhoaDieuTri.SelectedValue.ToString();
            nvi.PhuongPhapDieuTri = txtNhapVien_PPDieuTri.Text;
            nvi.MaPhongBenh = cboNhapVien_PhongBenh.SelectedValue.ToString();
            nvi.MaGiuongBenh = cboNhapVien_GiuongBenh.SelectedValue.ToString();
            nvi.NgayNhapVien = Convert.ToDateTime(dtPickerNhapVien_NgayNhapVien.Value.ToString());
            nvi.NgayXuatVienDK = Convert.ToDateTime(dtPickerNgayXuatVienDuKien.Value.ToString());
            nvi.TamUng = txtNhapVien_TamUng.Text;

            return nvi;
        }