//表头
   string strTitle = this.LiteralTitle.Text;
   //年月
   string strYearMonth = this.LiteralDate.Text;
   //填报人
   string strUserInfo = this.LiteralUserInfo.Text;
   Response.Clear();
　　        Response.Buffer = true;
　　        Response.Charset = "GB2312";   
   Response.AppendHeader("Content-Disposition", "online;filename=" + strYearMonth + strTitle + ".xls");
　　        Response.ContentEncoding = System.Text.Encoding.GetEncoding("GB2312");　　      
   Response.ContentType = "application/ms-excel";

   //关闭 ViewState
   this.EnableViewState = false ;
   System.IO.StringWriter tw = new System.IO.StringWriter();

   System.Web.UI.HtmlTextWriter hw = new HtmlTextWriter(tw);
   //获取control的HTML
   dgrdList.RenderControl(hw);
   //把HTML写回浏览器
   
   StringBuilder html = new StringBuilder();
   html
    .Append("<table cellspacing = \"0\" border = \"1\" >")
    .Append("<tr align = Center style = \"height:24px;\"><td colSpan=\""+ ViewState["DgrdCellCount"].ToString() +"\">"+ strTitle +"</td></tr>")
    .Append("<tr align = Center style = \"height:24px;\"><td colSpan=\""+ ViewState["DgrdCellCount"].ToString() +"\">"+ strYearMonth +"</td></tr>")
    .Append("<tr align = left style = \"height:24px;\"><td colSpan=\""+ ViewState["DgrdCellCount"].ToString() +"\">"+ strUserInfo +"</td></tr>")
    .Append("</table>");
   Response.Write(html.ToString() + tw.ToString());
   Response.End();

----------------------------------------------------------------

from:http://www.zxbc.cn/html/20080516/34394.html

protected void btnToExcel_Click(object sender, EventArgs e)
    {
        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.xls
        Response.AppendHeader("Content-Disposition", "attachment;filename=FileName.xls");
        Response.ContentEncoding = System.Text.Encoding.GetEncoding("GB2312");
        //设置导出文件的格式
        Response.ContentType = "application/ms-excel";
        //关闭ViewState
        EnableViewState = false;
        System.Globalization.CultureInfo cultureInfo = new System.Globalization.CultureInfo("ZH-CN", true);
        System.IO.StringWriter stringWriter = new System.IO.StringWriter(cultureInfo);
        System.Web.UI.HtmlTextWriter textWriter = new System.Web.UI.HtmlTextWriter(stringWriter);
        gvPersonList.RenderControl(textWriter);
        //把HTML写回浏览器
        Response.Write(stringWriter.ToString());
        Response.End();
    }
    //导出成Word文件
    protected void btnToWord_Click(object sender, EventArgs e)
    {
        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("Content-Disposition", "attachment;filename=FileName.doc");
        Response.ContentEncoding = System.Text.Encoding.GetEncoding("GB2312");
        ////设置导出文件的格式
        Response.ContentType = "application/ms-word";
        //关闭ViewState
        gvPersonList.EnableViewState = false;
        System.Globalization.CultureInfo cultureInfo = new System.Globalization.CultureInfo("ZH-CN", true);
        System.IO.StringWriter stringWriter = new System.IO.StringWriter(cultureInfo);
        System.Web.UI.HtmlTextWriter textWriter = new System.Web.UI.HtmlTextWriter(stringWriter);
        gvPersonList.RenderControl(textWriter);
        // //把HTML写回浏览器
        Response.Write(stringWriter.ToString());
        Response.End();
    }