ASP.NET MVC 4, C#: how to Download File

Question

I have uploaded a file into my database previously, now I want to download that file from my database.

Can anyone show me how? I am new to C# and ASP.NET MVC.

Controller :

public ActionResult Details(string id = null)
{
        Assignment assignment = db.Assignments.Find(id);

        if (assignment == null)
        {
            return HttpNotFound();
        }

        return View(assignment);
}

Model:

public string AssignmentID { get; set; }
public Nullable<System.DateTime> SubmissionDate { get; set; }
public string Status { get; set; }
[Range(0,100, ErrorMessage="Only Value between 0-100 is accepted.")]
public Nullable<decimal> Mark { get; set; }
public string Comments { get; set; }
public byte[] FileLocation { get; set; }

View:

<div class="display-label">
    <%: Html.DisplayNameFor(model => model.FileLocation) %>
</div>
<div class="display-field">
    <%: Html.DisplayFor(model => model.FileLocation) %>
</div>

Looks to be a duplicate of http://stackoverflow.com/questions/5826649/returning-a-file-to-view-download-in-mvc — David Hoerster, Aug 06 '14 at 16:50
there is nothing wrong with my answer..<%: Url.Action("Details","// your controller name//", new{ id = item.ID }) %>..is mazor part of answer.....thankzz..@WeakestInCoding.... — Kartikeya Khosla, Aug 06 '14 at 17:25

score 6 · Accepted Answer · answered Aug 06 '14 at 17:01

Since you have the a Stream or byte[] or a path of a file, you can use the File() method that comes from Controller base class, and respond this file as an ActionResult, for sample:

public ActionResult Details(string id = null)
{
     Assignment assignment = db.Assignments.Find(id);

     if (assignment == null)
     {
         return HttpNotFound();
     }

     return File(assigment.FileLocation, "content/type", "fileName.extension");
}

Remember to get the right content-type and add a fileName with the correct extension.

score 1 · Answer 2 · answered Aug 06 '14 at 16:54

1

Based on how you're retrieving the file from your database, you can use ASP.NET MVC's File() helper method to return your file to the client.

This blog article has a very good description of how to use the File() helper and what ends up getting returned.

Hope this helps.

answered Aug 06 '14 at 16:54

David Hoerster

28,421
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Ya this Helped Thanks a million =) – WeakTaenie Aug 06 '14 at 17:24

Kartikeya Khosla · Answer 3 · 2014-08-07T04:18:55.403

1

You have to use @url.action to display images on view :

View :

<%: Url.Action("ImageDetails","// your controller name//", new{ id = item.ID }) %>

and in your action:

public ActionResult ImageDetails(string id = null)
{
     Assignment assignment = db.Assignments.Find(id);

     return File(assignment.FileLocation, "content/type", "file.extension");
}

Remember to get the right content-type and add file correct extension otherwise file will not be rendered properly in view.

If you want only to download file not display then :-

public ActionResult Details(string id = null)
{
     Assignment assignment = db.Assignments.Find(id);

     return File(assignment.FileLocation, "content/type", "file.extension");
}

edited Aug 07 '14 at 04:18

answered Aug 06 '14 at 17:07

Kartikeya Khosla

18,743
8
43
69

What is it? Copied my awnser with and change it worst solution? A File cannot be rendred in View! – Felipe Oriani Aug 06 '14 at 17:20
@FelipeOriani....just try above code ..with url.action file will render on view... – Kartikeya Khosla Aug 06 '14 at 17:23
If it was not An Image, will it still display? i mean Docx or txt – WeakTaenie Aug 06 '14 at 17:32
@WeakestInCoding...yes anything can be displayed because while returning file in controller you are specifying content type and file extension also.... – Kartikeya Khosla Aug 06 '14 at 17:34
Erm i not sure how to Set it, <%: Url.Action("Details","Assignment", new{ id = Model.AssignmentID}) %> Did i set wrong – WeakTaenie Aug 06 '14 at 17:58
@WeakestInCoding...its correct..then pdf or txt is rendering or not?? – Kartikeya Khosla Aug 06 '14 at 18:00
file.extension what should I do If I want to download into more different format file – WeakTaenie Aug 07 '14 at 11:49
@WeakestInCoding..then store file extension values in database when you are storing files in database and retrieve file extenstion also while you are retrieving file from database.. – Kartikeya Khosla Aug 07 '14 at 11:51

ASP.NET MVC 4, C#: how to Download File

3 Answers3