export data to excel in asp.net

Page Language="C#" AutoEventWireup="true" EnableEventValidation="false"

public override void VerifyRenderingInServerForm(Control control) {
/* Confirms that an HtmlForm control is rendered for the specified ASP.NET
server control at run time. */
}

//Export to Excel from a GridView
protected void ExportToExcel() {
Response.Clear();
Response.Buffer = true;
Response.ContentType = "application/vnd.ms-excel";
Response.AddHeader("content-disposition", "attachment;filename=MyFiles.xls");

// for turkish support
Response.ContentEncoding = Encoding.GetEncoding("ISO-8859-9");
Response.Charset = "ISO-8859-9";

this.EnableViewState = false;

System.IO.StringWriter sw = new System.IO.StringWriter();
System.Web.UI.HtmlTextWriter htw = new System.Web.UI.HtmlTextWriter(sw);

gvFiles.RenderControl(htw);

Response.Write(sw.ToString());
Response.End();
}

http://blogs.msdn.com/erikaehrli/archive/2009/01/30/how-to-export-data-to-excel-from-an-asp-net-application-avoid-the-file-format-differ-prompt.aspx