public bool isDeleted { get; set; }

[HttpPost]
    [ValidateAntiForgeryToken]
    public ActionResult Create([Bind(Include = "srfId,Name,devId,clientId,isDeleted")] testSRF testSRF,)
    {
        if (ModelState.IsValid)
        {

            //code here to set default value of isDeletedValue even w/o the html.Dropdowonlist (if possible)

            db.testSRFs.Add(testSRF);
            db.SaveChanges();
            return RedirectToAction("Index");
        }

        ViewBag.devId = new SelectList(db.device1, "devId", "plateNo", testSRF.devId);
        return View(testSRF);
    }