最近有一个项目使用以前的ashx，不能使用FileResult，只有通过response返回拼接好的字符串。但是通过查阅资料拼接的字符串总是提示文件格式不匹配，虽然能正常打开，但是体验很不好，在此总结一下我的解决方法：
直接下载excel会提示格式不相符，稍微修改，下载成csv的就没问题了

• 后台：

/// <summary>
/// DataTable导出到Excel
/// </summary>
/// <param name="dt">DataTable类型的数据源</param>
/// <param name="FileType">文件类型</param>
/// <param name="FileName">文件名</param>
public void CreateExcel(HttpContext context, List<PB_SITE_BASIC> siteList, string FileName)
{//分割符string split = ",";HttpResponse Response = System.Web.HttpContext.Current.Response;Response.Clear();Response.Charset = "UTF-8";Response.Buffer = true;Response.ContentEncoding = System.Text.Encoding.GetEncoding("GB2312");Response.AppendHeader("Content-Disposition", "attachment;filename=\"" + System.Web.HttpUtility.UrlEncode(FileName, System.Text.Encoding.UTF8) + ".csv\"");Response.ContentType = "application/ms-excel";string colHeaders = string.Empty;string ls_item = string.Empty;int i = 0;int cl = siteList.Count;//添加表头ls_item += "站点编号" + split;ls_item += "站点名称" + split;ls_item += "车桩总数" + split;ls_item += "基站地址" + split;ls_item += "所属区域" + split;ls_item += "站点地址" + split;ls_item += "站点纬度" + split;ls_item += "站点经度" + split;ls_item = ls_item.Substring(0, ls_item.Length - 1) + "\n";foreach (var site in siteList){ls_item += site.SID.ToString() + split;ls_item += site.NAME.ToString() + split;ls_item += site.CAPACITY.ToString() + split;ls_item += site.BASESTATION_ID.ToString() + split;ls_item += site.REGION_ID.ToString() + split;ls_item += site.ADDRESS.ToString() + split;ls_item += site.LAT.ToString() + split;ls_item += site.LNG.ToString() + split;ls_item += "\n";Response.Output.Write(ls_item);ls_item = string.Empty;}Response.Output.Flush();Response.End();
}

• 前台

//导出
$("#btExport").click(function () {window.location = "ExportSiteBasic.ashx";
});