gridview数据如何导出到word，excel

  if (DropDownList2.SelectedValue == "导出为word格式")
            {
                Response.Clear();
                Response.BufferOutput = true; 　　　　
                //设定输出的字符集 　　　　
                Response.Charset="GB2312"; 　　　　
                //假定导出的文件名为FileName.doc 　　　　
                Response.AppendHeader("ContentDisposition","p_w_upload;filename=FileName.doc"); 　　　　
                Response.ContentEncoding=System.Text.Encoding.GetEncoding("GB2312"); 　　　　
                ////设置导出文件的格式 　　　　
                Response.ContentType="application/ms-word";

                StringWriter sw = new StringWriter();
                HtmlTextWriter htw = new HtmlTextWriter(sw);

                gvPersonList.RenderControl(htw);
                Response.Write(sw.ToString());

                Response.End();
            }
            if (DropDownList2.SelectedValue == "导出为excel格式")
            {
              Response.ClearContent();
              Response.Charset = "GB2312";
              Response.ContentEncoding = System.Text.Encoding.UTF8;
              Response.AddHeader("content-disposition", "p_w_upload; filename=excel.xlsx");
              Response.ContentType = "application/ms-excel";
              StringWriter sw = new StringWriter();
              HtmlTextWriter htw = new HtmlTextWriter(sw);
              gvPersonList.RenderControl(htw);
             Response.Write(sw.ToString());
             Response.End();
            }