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>

Answer 1

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.