verileri gridwiev e aktar daha sonra aşağıdaki kodu bir butonun eventine yaz excelle aktarmış olursun
HtmlForm form = new HtmlForm();
HttpContext.Current.Response.ContentEncoding = System.Text.Encoding.GetEncoding("windows-1254");
HttpContext.Current.Response.Charset = "windows-1254";
string dosya = "attachment;filename=ExcellListesi.xls";
Response.ClearContent();
Response.AddHeader("content-disposition", dosya);
Response.ContentType = "appliction/ms-excel";
StringWriter sw = new StringWriter();
HtmlTextWriter hw = new HtmlTextWriter(sw);
form.Controls.Add(grdListe);
this.Controls.Add(form);
form.RenderControl(hw);
Response.Write(sw.ToString());
Response.End();