[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Create([Bind(Include = "LastName, FirstMidName, EnrollmentDate")]Student student, HttpPostedFileBase upload)
{
    try
    {
        if (ModelState.IsValid)
        {
            if (upload != null && upload.ContentLength > 0)
            {
                var avatar = new File
                {
                    FileName = System.IO.Path.GetFileName(upload.FileName),
                    FileType = FileType.Avatar,
                    ContentType = upload.ContentType
                };
                using (var reader = new System.IO.BinaryReader(upload.InputStream))
                {
                    avatar.Content = reader.ReadBytes(upload.ContentLength);
                }
                student.Files = new List<File> { avatar };
            }
            db.Students.Add(student);
            db.SaveChanges();
            return RedirectToAction("Index");
        }
    }
    catch (RetryLimitExceededException /* dex */)
    {
        //Log the error (uncomment dex variable name and add a line here to write a log.
        ModelState.AddModelError("", "Unable to save changes. Try again, and if the problem persists see your system administrator.");
    }
    return View(student);
}

[HttpPost, ActionName("Edit")]
[ValidateAntiForgeryToken]
public ActionResult EditPost(int? id, HttpPostedFileBase upload)
{
    if (id == null)
    {
        return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
    }
    var studentToUpdate = db.Students.Find(id);
    if (TryUpdateModel(studentToUpdate, "",
        new string[] { "LastName", "FirstMidName", "EnrollmentDate" }))
    {
        try
        {
            if (upload != null && upload.ContentLength > 0)
            {
                if (studentToUpdate.Files.Any(f => f.FileType == FileType.Avatar))
                {
                    db.Files.Remove(studentToUpdate.Files.First(f => f.FileType == FileType.Avatar));
                }
                var avatar = new File
                {
                    FileName = System.IO.Path.GetFileName(upload.FileName),
                    FileType = FileType.Avatar,
                    ContentType = upload.ContentType
                };
                using (var reader = new System.IO.BinaryReader(upload.InputStream))
                {
                    avatar.Content = reader.ReadBytes(upload.ContentLength);
                }
                studentToUpdate.Files = new List<File> { avatar };
            }
            db.Entry(studentToUpdate).State = EntityState.Modified;
            db.SaveChanges();

            return RedirectToAction("Index");
        }
        catch (RetryLimitExceededException /* dex */)
        {
            //Log the error (uncomment dex variable name and add a line here to write a log.
            ModelState.AddModelError("", "Unable to save changes. Try again, and if the problem persists, see your system administrator.");
        }
    }
    return View(studentToUpdate);
}