asp.net gv导出excel

protected void btnExcel_Click(object sender, EventArgs e)
{
Response.Clear();

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

Response.ContentType = "application/vnd.xls";

System.IO.StringWriter stringWrite = new System.IO.StringWriter();

System.Web.UI.HtmlTextWriter htmlWrite =
new HtmlTextWriter(stringWrite);

gvDB.RenderControl(htmlWrite);

Response.Write(stringWrite.ToString());

Response.End();
}