if(DataGrid1.Items.Count==0)
    {
     Response.Write("<script>alert('对不起,你没有查询到任何记录,不能导出数据')</script>");
    }
    else
    {     

     Response.Clear();
     Response.Buffer= true;
     Response.Charset="GB2312";
     Response.AppendHeader("Content-Disposition","attachment;filename=FileName.xls");
     Response.ContentEncoding=System.Text.Encoding.GetEncoding("GB2312");
     //设置输出流为简体中文
     Response.ContentType = "application/ms-excel";
     //设置输出文件类型为excel文件。
     this.EnableViewState = false;
     System.Globalization.CultureInfo myCItrad = new System.Globalization.CultureInfo("ZH-CN",true);
     System.IO.StringWriter oStringWriter = new System.IO.StringWriter(myCItrad);
     System.Web.UI.HtmlTextWriter oHtmlTextWriter = new System.Web.UI.HtmlTextWriter(oStringWriter);
     DataGrid1.RenderControl(oHtmlTextWriter);
     Response.Write(oStringWriter.ToString());
     Response.End();

}