Reading files to bytes not working properly in project

Question

I have a weird problem. I am making a C# MVC application which generates PDF's and offers them for download with a download button.

public ActionResult Download()
{
    string url = (string)TempData["url"];

    byte[] thePdf = System.IO.File.ReadAllBytes(url);

    return File(thePdf, "application/pdf");
}

All of a sudden I can't properly convert a PDF file to byte[] , either with File.ReadAllBytes() or with a MemoryStream (or any other stream).

When I used a MemoryStream I got an InvalidOperationException on both the ReadTimeOut and WriteTimeOut .

I implemented the code mentioned above in a new C# MVC Project and there everything worked fine. So the issue must be with the project that i'm working in.

Answer 1

If your url is remote url, you should use WebClient to download data like below.

I tried to reproduce your code and it worked.

 public ActionResult Download()
        {
            string url = (string)TempData["url"];

            url = "http://www.iuh.edu.vn/Tuyensinh/QC/TomTatQuyCheThiTHPT2018.pdf";

            using (var client = new WebClient())
            {
                // read data
                byte[] thePdf = client.DownloadData(url);

                return File(thePdf, "application/pdf");

            }

            //byte[] thePdf = System.IO.File.ReadAllBytes(url);

            //return File(thePdf, "application/pdf");
        }

In cshtml:

<input type="button" value="Download" onclick="window.location.href='/YourController/Download'" />