将DataGrid或GridView中的数据生成Excel

 void ToExcel(System.Web.UI.Control ctl, string FileName)
    {
        //设置网络输出流的HTTP字符集为UTF-8，Current为当前 HTTP 请求获取 HttpContext 对象
        HttpContext.Current.Response.Charset = "GB2312";
        HttpContext.Current.Response.ContentEncoding = System.Text.Encoding.Default;
        //设置输出流HTTPMIME类型为excel
        HttpContext.Current.Response.ContentType = "application/ms-excel";
        //将HTTP头添加到输出流
        HttpContext.Current.Response.AppendHeader("Content-Disposition", "attachment;filename=" + "" + FileName + ".xls");
        //不保存该控件的视图状态
        ctl.Page.EnableViewState = false;
        System.IO.StringWriter sw = new System.IO.StringWriter();
        //将文本写入到输出流
        System.Web.UI.HtmlTextWriter hw = new System.Web.UI.HtmlTextWriter(sw);
        //将服务器控件的内容输出到HtmlTextWriter对象中
        ctl.RenderControl(hw);
        //StringWriter.ToString返回包含迄今为止写入到当前 StringWriter 中的字符的字符串
        HttpContext.Current.Response.Write(sw.ToString());
        HttpContext.Current.Response.End();

    }

    //这个事件必须加
    public override void VerifyRenderingInServerForm(Control control)
    {
        //base.VerifyRenderingInServerForm(control);
    }