Response.TransmitFile does not work in mvc 5

Question

I have a mvc 5 application, I save letters files in folder inside folder like (~\Files\Letters) and I save the physical path in database, uploading letters files to (~\Files\Letters) works fine and saving the physical path works fine, the problem is downloading a letter file to client machine, I have tried using Webclient and Response both don't work and don't give any error, here is the code for downloading a letter file using Response.

 [HttpPost]
    public void open(int id)
    {

        string path = "";

        path = db.tblLetters.Where(t => t.ID == id).SingleOrDefault().LetterImg;
        string fileName = path.Substring(path.LastIndexOf(@"\")+1);
        string p = Server.MapPath("~/Files/LettersImgs/" + fileName);

        Response.Clear();
        Response.AddHeader("content-disposition", "attachment; filename=" + fileName);
        Response.ContentType = "application/octet-stream";
        Response.TransmitFile(p);
        Response.End();

    }

`public void open(int id)` => this should be `public ActionResult open(int id)` and use `return File(p, "application/octet-stream", fileName)` to return the file (note: you must use `HttpGet` to enable downloading). — Tetsuya Yamamoto, Sep 28 '18 at 04:44

score 2 · Answer 1 · answered Sep 28 '18 at 04:59

Rather than using old-style Response.TransmitFile, you can use FilePathResult to return file directly from server's file path. Change return type from void to ActionResult (or FileResult) and use [HttpGet] instead of [HttpPost], and do return File(...) to let user download the file like this example below:

[HttpGet]
public ActionResult Open(int id)
{
    string path = "";

    path = db.tblLetters.Where(t => t.ID == id).SingleOrDefault().LetterImg;
    string fileName = path.Substring(path.LastIndexOf(@"\")+1);
    string p = Server.MapPath("~/Files/LettersImgs/" + fileName);

    return File(p, "application/octet-stream", fileName);
}

Related issue: How to download a file to client from server?

Response.TransmitFile does not work in mvc 5

1 Answers1