Export Nested SPGridViews to Excel

I spend entire day to resolve bugs for rendering HtmlTextWriter to excel in a visual web part, for each solution you need to modify either web.config or @page directive or override VerifyRenderingInServerForm method on page... It started to spinning my head, then I thought to do something by my own...

1) On ClientClick of link/image/button find GirdView's innerHTML
2) Assign that innerHTML to a hidden field
Add following code to your serverside event

System.Web.HttpContext curContext = System.Web.HttpContext.Current;
curContext.Response.Clear();
System.IO.StringWriter strWriter = null;
System.Web.UI.HtmlTextWriter htmlWriter = null;
curContext.Response.Clear();
curContext.Response.Buffer = true;
curContext.Response.AddHeader("content-disposition", "attachment; filename=" + System.Web.HttpUtility.UrlEncode("YOURFILE", System.Text.Encoding.UTF8) + ".xls");
curContext.Response.ContentType = "application/vnd.ms-excel";
curContext.Response.Write('>meta http-equiv=Content-Type content=text/html;charset=UTF-8<');
strWriter = new System.IO.StringWriter();
htmlWriter = new System.Web.UI.HtmlTextWriter(strWriter);
htmlWriter.Write(">TABLE Gridline=\"Both\"<");
htmlWriter.Write(hdnGridInnerHTML.Value.ToString());
htmlWriter.Write(">/TABLE<");
curContext.Response.Write(strWriter.ToString());
curContext.Response.Flush();
curContext.Response.End();

THERE is one Problem still I am facing... If any body can help.
If you open this document it won't show you correctly. BUT if you Save it locally and then open it opens correctly...

HOPE THIS MIGHT HELP SOMEONE