mvc4 how to create download button

i would like to create a button in my details view .when clicking that button i want to download it from database , i upload it perfectly in my databese

 

 

public ActionResult AddDocument(Document document)
{
if (document.UploadDocument != null)
{
using (var ms = new MemoryStream())
{
document.UploadDocument.InputStream.CopyTo(ms);
document.DocumentImage = ms.GetBuffer();
}
}
db.Documents.Add(document);
db.SaveChanges();
ModelState.Clear();
return View();

} 

 

ACTION:

 

@foreach (var item in Model)
{




@**@
@**@


sn++;
}

SNo	NAME	DESCRIPTION	DOWNLOAD
@sn	@Html.DisplayFor(s => item.Name)	@Html.DisplayFor(s => item.Description)	Download	@Html.ActionLink((s=>item.DocumentImage),"DownloadFile")	@Html.ActionLink("Download","DownloadFile")