Export To Excel using Datagridview not working

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C#

ASP.NET

Hello Friends
i am trying to export datagridview but its not work . here is my code..

protected void BtnExcel_Click(object sender, ImageClickEventArgs e)
    {
        Response.Clear();
        Response.AddHeader("content-disposition", "attachment;filename=OrderReports.xls");
        Response.Charset = "";
        Response.ContentType = "application/vnd.xls";
        StringWriter sw = new StringWriter();
        HtmlTextWriter htw = new HtmlTextWriter(sw);
        GrdOrder.RenderControl(htw);
        Response.Write(sw.ToString());
        Response.End();

    }

code run successfully when i come to my website and see the inspect element then its give the error like this :-

Uncaught Sys.WebForms.PageRequestManagerParserErrorException: Sys.WebForms.PageRequestManagerParserErrorException: The message received from the server could not be parsed. Common causes for this error are when the response is modified by calls to Response.Write(), response filters, HttpModules, or server trace is enabled.
Details: Error parsing near '