export parent child gridview in excel using c#

Question

I am using store procedure for retriving data for both parent gridview as welll as child gridview,

 

Response.ContentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";

Response.AddHeader("content-disposition", "attachment;filename= = CustomerAging.xls");

Response.ContentEncoding = Encoding.UTF8;

StringWriter tw = new StringWriter();

HtmlTextWriter hw = new HtmlTextWriter(tw);

gridCustomeraging.RenderControl(hw);

Response.Write(tw.ToString());

Response.End();