using sb.append or not?

Hi there!
I have two pages. redirect.aspx page, which sends a silly id to detail.aspx page. My question here is on the details.aspx and details.aspx.cs page:)
This is my details.aspx.cs page
 
protected void Page_Load(object sender, EventArgs e) {         DataSet dsProducts = new DataSet();
        dsProducts.ReadXml(Server.MapPath("bugun.xml"));
        DataView dvProducts = new DataView(dsProducts.Tables["inv4"]);
        dvProducts.Sort = "id";

        int rowIndex = dvProducts.Find(Request.QueryString["id"]);
        string pic, prod, type;
       
...