Question

Below is the offending code, I download a csv however it appends the page source to the bottom any ideas on how to prevent this?

            var priceList = Test();
            const string downloadName = "PriceList.csv";
            var fs = new FileStream(downloadName, FileMode.Create);

            var csv = new CsvHelper.CsvHelper(fs);
            csv.Writer.WriteRecords(priceList);
            Response.ClearContent();

            //not sure what the correct content type is. This is probally wrong
            Response.ContentType = "application/xls";
            //Setting size is optional               
            Response.AddHeader("Content-Disposition",
               "attachment; filename=" + downloadName + "; size=" + fs.Length.ToString());
            var fn = fs.Name;
            fs.Close();
            loadingImage.Visible = false;
            Response.TransmitFile(fn);
            Response.Flush();

Answer 1

Call Response.End().

Also, why save the file just to resend it? At best this is wasteful, but also if you’re reusing the name then you’ve a race-condition if two people hit this page at the same time. Instead of sending the file, use var csv = new CsvHelper.CsvHelper(Response.OutputStream) so you write straight to the browser (you’ll have to send your headers first though).

Also, the content-type for CSV files is text/csv.