将DataGridview的内容保存到Excel

protected void btnprint_Click(object sender, EventArgs e)
{
　　Response.Charset = "GB2312";
　　Response.ContentEncoding = System.Text.Encoding.UTF7;
　　Response.AppendHeader("Content-Disposition", "attachment;filename=" + HttpUtility.UrlEncode("考勤统计记录.xls", Encoding.UTF8).ToString());

　　Response.ContentType = "application/ms-excel";
　　this.EnableViewState = false;
　　StringWriter tw = new StringWriter();
　　HtmlTextWriter hw = new HtmlTextWriter(tw);
　　gvSignInfoStatistic.RenderControl(hw);
　　string print = string.Format("

制表人 : {0}   上报日期 : {1}", lblReportUser.Text, lblReportTime.Text);
　　hw.InnerWriter.Write(print);
　　Response.Write(tw.ToString());
　　Response.End();
}