Export Gridview to Excel not working

Hello, I have the following code, I put this into App_code.
 
public static void PrepareGridViewForExport(Control gv)
    {

        LinkButton lb = new LinkButton();
        Literal l = new Literal();
        string name = String.Empty;
        for (int i = 0; i < gv.Controls.Count; i++)        {

            if (gv.Controls[i].GetType() == typeof(LinkButton))
            {
                l.Text = (gv.Controls[i] as LinkButton).Text;
                gv.Controls.Remo ...