HOW TO CHANGE COLOUR

Using HtmlTextWriter we can able to achieve , please try .

        string FileName = "";
        Response.Clear();
        Response.AddHeader("content-disposition", "attachment;filename=" expExcel.xls "");
        Response.Charset = "";
        Response.Cache.SetCacheability(HttpCacheability.NoCache);
        Response.ContentType = "application/vnd.xls";
        System.IO.StringWriter oWriter = new System.IO.StringWriter();
        System.Web.UI.HtmlTextWriter htmlWrite = new HtmlTextWriter(oWriter);
        Table.RenderControl(htmlWrite);
        Response.Write(oWriter.ToString());
        Response.End();
 
If you're facing any error in Response.End (while debug ) , please check my forum to resolve the same in http://www.c-sharpcorner.com/Forums/ShowMessages.aspx?ThreadID=82416
 
 
If it helps you , please mark as answer.