// Hàm tự viết
        // Thêm phiếu nhập
        public void Them(CtPhieuNhap ct)
        {
            string       sql         = "insert into CT_PhieuNhap values(@MaPhieuNhap,@SP_ID,@SoLuongNhap,@DonGiaNhap)";
            SqlParameter maphieunhap = new SqlParameter("@MaPhieuNhap", ct.MaPhieuNhap);
            SqlParameter spid        = new SqlParameter("@SP_ID", ct.SP_ID);
            SqlParameter dongianhap  = new SqlParameter("@DonGiaNhap", ct.DonGiaNhap);
            SqlParameter soluongnhap = new SqlParameter("@SoLuongNhap", ct.SoLuongNhap);

            SqlDatabase.ExecuteNonQuery(sql, CommandType.Text, maphieunhap, spid, dongianhap, soluongnhap);
        }
        // Hàm tự viết
        // Thêm phiếu nhập
        public void Them(CtPhieuNhap ct)
        {
            string sql = "insert into CT_PhieuNhap values(@MaPhieuNhap,@SP_ID,@SoLuongNhap,@DonGiaNhap)";
            SqlParameter maphieunhap = new SqlParameter("@MaPhieuNhap", ct.MaPhieuNhap);
            SqlParameter spid = new SqlParameter("@SP_ID", ct.SP_ID);
            SqlParameter dongianhap = new SqlParameter("@DonGiaNhap", ct.DonGiaNhap);
            SqlParameter soluongnhap = new SqlParameter("@SoLuongNhap", ct.SoLuongNhap);

            SqlDatabase.ExecuteNonQuery(sql, CommandType.Text, maphieunhap, spid, dongianhap, soluongnhap);
        }
        public List <CtPhieuNhap> HienThiCtPhieuNhap(CtPhieuNhap ct)
        {
            List <CtPhieuNhap> data        = new List <CtPhieuNhap>();
            string             sql         = "select MaPhieuNhap,sp.SP_ID,sp.TenSP,DonGiaNhap,SoLuongNhap from CT_PhieuNhap ct, SanPham sp where ct.SP_ID=sp.SP_ID and MaPhieuNhap=@MaPhieuNhap";
            SqlParameter       maphieunhap = new SqlParameter("@MaPhieuNhap", ct.MaPhieuNhap);
            SqlDataReader      rd          = SqlDatabase.ExecuteQueryWithDataReader(sql, CommandType.Text, maphieunhap);

            if (rd.HasRows)
            {
                while (rd.Read())
                {
                    ct = new CtPhieuNhap()
                    {
                        MaPhieuNhap = rd[0].ToString(),
                        SP_ID       = int.Parse(rd[1].ToString()),
                        TenSP       = rd[2].ToString(),
                        DonGiaNhap  = float.Parse(rd[3].ToString()),
                        SoLuongNhap = int.Parse(rd[4].ToString()),
                    };
                    data.Add(ct);
                }
            }
            return(data);
        }
        public List<CtPhieuNhap> HienThiCtPhieuNhap(CtPhieuNhap ct)
        {
            List<CtPhieuNhap> data = new List<CtPhieuNhap>();
            string sql = "select MaPhieuNhap,sp.SP_ID,sp.TenSP,DonGiaNhap,SoLuongNhap from CT_PhieuNhap ct, SanPham sp where ct.SP_ID=sp.SP_ID and MaPhieuNhap=@MaPhieuNhap";
            SqlParameter maphieunhap = new SqlParameter("@MaPhieuNhap", ct.MaPhieuNhap);
            SqlDataReader rd = SqlDatabase.ExecuteQueryWithDataReader(sql, CommandType.Text, maphieunhap);
            if (rd.HasRows)
            {
                while (rd.Read())
                {
                    ct = new CtPhieuNhap()
                    {
                        MaPhieuNhap = rd[0].ToString(),
                        SP_ID = int.Parse(rd[1].ToString()),
                        TenSP = rd[2].ToString(),
                        DonGiaNhap = float.Parse(rd[3].ToString()),
                        SoLuongNhap = int.Parse(rd[4].ToString()),

                    };
                    data.Add(ct);
                }
            }
            return data;
        }