Code to export gridview data to ecxel

Response.Clear();
          Response.AddHeader("content-disposition", "attachment;filename=FileName.xls");
          Response.Buffer = true;
          Response.ContentType = "application/vnd.xls";
          Response.Charset = "";
          EnableViewState = false;
          System.IO.StringWriter oStringWriter = new System.IO.StringWriter();
          System.Web.UI.HtmlTextWriter oHtmlTextWriter = new System.Web.UI.HtmlTextWriter(oStringWriter);
          ClearControls(grd);
          GridView1.RenderControl(oHtmlTextWriter);
          Response.Write(oStringWriter.ToString());
          Response.End();