export to excel

[Mike]

On my page I'm using an updatepanel, updateProgress, and a ModalProgress,
everything works great But when I try to export my GridView to excel I'm
getting the following error message:

Sys.WebForms.Pa geRequestManage rParserErrorExc eption: The message received
from the server could not be parsed. Common cause for this error are when
the response is modified by calls to Response.Write( ), response filters,
HttpModules, or server trace is enable.

Details: Error parsing near '<div>
<table cells'.


How can I get my GridView to export to excel when I have it within the panel
and using the updateProgress and ModalProgress panel with it?
Here is my export code;

Response.Clear( );
Response.AddHea der("content-disposition", "attachment ;
filename=output .xls");
Response.Charse t = "";
Response.Conten tType = "applicatio n/ouput.xls";
System.IO.Strin gWriter stringWrite = new
System.IO.Strin gWriter();
System.Web.UI.H tmlTextWriter htmlWrite = new
HtmlTextWriter( stringWrite);
gOutput.RenderC ontrol(htmlWrit e);
Response.Write( stringWrite.ToS tring());
Response.End();