public void LoadDSSP(bool TrangThai)
        {
            BUS_HoaDon bus = new BUS_HoaDon();
            DataTable  dt  = new DataTable();

            dt = bus.LoadDSHD(TrangThai);
            gvHoaDon.DataSource = dt.DefaultView;
            gvHoaDon.DataBind();
        }
        protected void gvHoaDon_PageIndexChanging(object sender, GridViewPageEventArgs e)
        {
            bool trangthai = bool.Parse(ddlHoaDon.SelectedValue);

            Session["hdPage"] = e.NewPageIndex;
            BUS_HoaDon bus = new BUS_HoaDon();
            DataTable  dt  = new DataTable();

            dt = bus.LoadDSHD(trangthai);
            gvHoaDon.DataSource = dt.DefaultView;
            gvHoaDon.PageIndex  = e.NewPageIndex;
            gvHoaDon.DataBind();
        }
        protected void btnCapNhat_Click(object sender, EventArgs e)
        {
            if (Session["MaHoaDon"] != null)
            {
                BUS_HoaDon bus = new BUS_HoaDon();

                int    mahd = int.Parse(Session["MaHoaDon"].ToString());
                HoaDon hd   = new HoaDon();
                hd.MAHD           = mahd;
                hd.DIACHIGIAOHANG = txtDiaChi.Text;
                hd.TRANGTHAI      = bool.Parse(ddlTrangThai.SelectedValue);

                bus.CapNhatHD(hd);
                if (hd.TRANGTHAI.Equals(true))
                {
                    foreach (GridViewRow row in gvCTHD.Rows)
                    {
                        int masp = int.Parse(row.Cells[1].Text);
                        bus.CapNhatSoLuong(masp);
                    }
                }
                lblThongBao.Text = "";



                bool      trangthai = bool.Parse(ddlHoaDon.SelectedValue);
                int       page      = int.Parse(Session["hdPage"].ToString());
                DataTable dt        = new DataTable();
                dt = bus.LoadDSHD(trangthai);
                gvHoaDon.DataSource = dt.DefaultView;
                gvHoaDon.PageIndex  = page;
                gvHoaDon.DataBind();
                Session["MaHoaDon"] = null;
            }
            else
            {
                lblThongBao.Text = "Chưa chọn hóa đơn cần cập nhật.";
            }
        }