webapi下载文件

[HttpGet]
        public IHttpActionResult ExportData()
        {

            ...
            var dt = ExcelHelper.ListToDataTable(list);
            var fileName = SysConfig.WebTempPath + Guid.NewGuid().ToString() + ".xls";
            ExcelHelper.ExportToFile(dt,fileName);
            
　　　　　　　　//http://www.cnblogs.com/enternal/p/5417519.html
            HttpResponseMessage httpResponseMessage = new HttpResponseMessage(HttpStatusCode.OK);
            FileStream fileStream = File.OpenRead(fileName);
            httpResponseMessage.Content = new StreamContent(fileStream);
            httpResponseMessage.Content.Headers.ContentType = new MediaTypeHeaderValue("application/octet-stream");
            httpResponseMessage.Content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment")
            {
                FileName =HttpUtility.UrlEncode(Path.GetFileName(fileName))
            };

            return ResponseMessage(httpResponseMessage);

        }

DF1E31DE-768E-43D7-B1DB-DE10BD031E13 From:http://www.cnblogs.com/xuejianxiyang/p/7802365.html