public ActionResult Edit(NCKH nCKH)
        {
            var files = Request.Files;

            if (files.Count == 1)
            {
                var file = files[0];
                if (file != null && file.ContentLength > 0)
                {
                    var name_file = $"{DateTime.Now.ToString("hhmmssddMMyyyy")}_{Path.GetFileName(file.FileName)}";
                    var path      = "/Content/Upload/" + name_file;
                    file.SaveAs(Server.MapPath(path));
                    nCKH.TaiLieu = path;
                }
            }

            if (nCKH.MaNCKH > 0)
            {
                db.Entry(nCKH).State = EntityState.Modified;
            }
            else
            {
                db.NCKHs.Add(nCKH);
            }
            db.SaveChanges();
            return(RedirectToAction("Detail", "GV", new { id = nCKH.MaGV, tab = 2 }));
        }
        // GET: AdminCP/NCKHs/Delete/5
        public JsonResult Delete(int?id)
        {
            NCKH nCKH = db.NCKHs.Find(id);

            db.NCKHs.Remove(nCKH);
            return(Json(db.SaveChanges()));
        }
        // GET: AdminCP/NCKHs/Edit/5
        public ActionResult Edit(int?id, int MaGV)
        {
            NCKH nCKH = new NCKH()
            {
                MaGV = MaGV
            };

            if (id != null)
            {
                nCKH = db.NCKHs.Find(id);
                if (nCKH == null)
                {
                    return(HttpNotFound());
                }
            }
            return(View(nCKH));
        }