public ActionResult Delete(int? articleId, int? estimateId)
{
    if(articleId == null || estimateId == null)
    {
        return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
    }
    Enroll enroll = db.Enrolls.Find(estimateId, articleId);
    if(enroll == null)
    {
        TempData["message"] = "Оценката не е намерена! Моля, опитайтено отново!";
        return RedirectToAction("NotFound", "Home");
    }

    db.Enrolls.Remove(enroll);
    db.SaveChanges();

    return RedirectToAction("Index", "Enrolls");
}