To create random number and adding rows from one table to another

  protected void btn_checkout_Click(object sender, EventArgs e)
    {
        string chars="ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
        Random random=new Random();
        string result=new string(Enumerable.Repeat(chars,10).Select(s=>s[random.Next(s.Length)]).ToArray());
        Session["corder"] = result;
        DateTime time = DateTime.Now.Date;
        DataTable dt = (DataTable)Session["cart"];

        Label username = new Label();
        Label email = new Label();
        Label address = new Label();
        Label country = new Label();
        Label state = new Label();
        Label city = new Label();
        Label pincode = new Label();

        for (int j = 0; j < dt.Rows.Count; j++)
        {
            dl.username = Session["usename"].ToString();           
            DataSet ds = new DataSet();
            ds = bl.select_user(dl);

            foreach (DataRow row in ds.Tables[0].Rows)
            {
                username.Text = row[1].ToString();
                email.Text = row[2].ToString();
                address.Text = row[5].ToString();
                country.Text = row[6].ToString();
                state.Text = row[7].ToString();
                city.Text = row[8].ToString();
                pincode.Text = row[9].ToString();
            }
            dl.order_code =result;
            dl.order_date = time;
            dl.p_id = Convert.ToInt16(dt.Rows[j]["p_id"]);
            dl.products_id = Convert.ToInt16(dt.Rows[j]["Product_id"]);
            dl.category = dt.Rows[j]["Category"].ToString();
            dl.product_name = dt.Rows[j]["Product_name"].ToString();
            dl.price = Convert.ToInt16(dt.Rows[j]["Price"]);
            dl.qty = Convert.ToInt16(dt.Rows[j]["qty"]);
            dl.tprice = Convert.ToInt16(dt.Rows[j]["tprice"]);
            dl.payable_amount = Convert.ToInt16(lbltotal.Text);
            dl.username = username.Text;
            dl.email = email.Text;
            dl.address = address.Text;
            dl.country = country.Text;
            dl.state = state.Text;
            dl.city = city.Text;
            dl.pincode = Convert.ToInt32(pincode.Text);
            bl.insert_order(dl);                                             
        }