如何通过c＃代码隐藏gridview列，但想要访问它的值

Question

我想要隐藏gridview列，但我仍然希望访问其值，因为销售是针对代码列值完成的。这是我的代码 我想隐藏第一列（代码）这里是我的gridview代码..它不应该在运行时显示

DataTable dt;
    private void MakeDataTable()
    {
        dt.Columns.Add("Code");
        dt.Columns.Add("DESC");
        dt.Columns.Add("Size");
        dt.Columns.Add("QTY");
        dt.Columns.Add("Price");
    }
    private void AddToDataTable()
    {
        string cat;
        string brnd;
        string cat_brnd;
        if (txtSKU.Text != "" & txtqnt.Text != "")
        {
            int quantity = 0;

            con = new SqlConnection(ConfigurationManager.ConnectionStrings["db"].ConnectionString);
            con.Open();
            //cmd = new SqlCommand("SELECT tbl_Product.strProductName,s.strSize,clr.strColorName, tbl_ItemDetail.strSalePrice,tbl_ItemDetail.nActualQuant FROM tbl_ItemDetail INNER JOIN tbl_Product ON tbl_ItemDetail.np_id = tbl_Product.np_id inner join tbl_Size s on tbl_ItemDetail.ns_id=s.ns_id inner join tbl_Color clr on tbl_ItemDetail.nclr_id=clr.nclr_id where tbl_ItemDetail.bnSKU='" + txtSKU.Text + "' ", con);
            cmd = new SqlCommand("select c.strCategoryName,id.bnSKU,id.strBrand,s.nSizeCode,id.nActualQuant,id.strSalePrice from tbl_ItemDetail id inner join tbl_Size s on id.ns_id=s.ns_id inner join tbl_Category c on id.nc_id=c.nc_id where id.bnSKU='" + txtSKU.Text + "' and id.bisDeleted='False'", con);
            sdr = cmd.ExecuteReader();
            cmd.Dispose();

            while (sdr.Read())
            {
                DataRow dr = dt.NewRow();
                quantity = Convert.ToInt32(sdr["nActualQuant"].ToString());
                cat = sdr["strCategoryName"].ToString();
                brnd = sdr["strBrand"].ToString();
                cat_brnd = "" + cat + "-" + brnd;

                if (quantity != 0)
                {

                    dr["Code"] = sdr["bnSKU"].ToString();
                    dr["DESC"] = cat_brnd.ToString();
                    dr["Size"] = sdr["nSizeCode"].ToString();
                    dr["QTY"] = txtqnt.Text;
                    dr["Price"] = sdr["strSalePrice"].ToString();

                    dt.Rows.Add(dr);

                }
                else
                { 
                    lbl_msg.Text = "Not In stock"; 
                }

            }
            cmd.Parameters.Clear();
            sdr.Close();


            con.Close();
        }
        else
        {
            lbl_msg.Text = "Please Select Product to add in purchae List";
        }
    }
    private void BindGrid()
    {
        gvsale.DataSource = dt;
        gvsale.DataBind();
        gvsale.Columns[0].Visible = false;
    }