string goumailiang = TextBox3.Text;    //goumailiang是用户输入的购买数量         

            int goumailiang1 = Convert.ToInt32(goumailiang);





            if (kc <= 0)

            {

                Response.Write("<script>alert('谢谢您的关注，本产品已售罄');document.location=document.location;</script>");

            }

            else

            {

                if (kc >= goumailiang1)

                {

                    Session["text"] = goumailiang1;

                   // response.redirect("BuyCar.cs?shuliang={0}", goumailiang1 );

                    float price = BuyCar.GetPriceByGoodsID(id);

        String shuliang = (DataTable)Session["text"];

       



        //检查表中是否存在同名的订购物品

        if (GoodsIsExist(GoodsID, MemberID))

        {

            //执行update语句，让同名的商品数量+1

            sql = string.Format("update tb_BuyInfo set Number="+shuliang +",SumPrice=("+shuliang +")*{0} where GoodsID={1} and MemberID={2}", Price, GoodsID, MemberID);

            SqlCommand cmd = new SqlCommand(sql, conn);

            cmd.ExecuteNonQuery();

            cmd.Dispose();

        }



        else

        {

            sql = string.Format("insert into tb_BuyInfo(GoodsID,MemberID,Number,SumPrice) values({0},{1},{2},{3})", GoodsID, MemberID, Num, Price);//默认订购1件商品，总价格就是商品单价

            SqlCommand cmd = new SqlCommand(sql, conn);

            cmd.ExecuteNonQuery();

            cmd.Dispose();

        }

        conn.Close();