public ActionResult Create(INVENTARIO_PDV inventario_pdv)
        {
            if (ModelState.IsValid)
            {
                db.INVENTARIO_PDV.Add(inventario_pdv);
                db.SaveChanges();
                return RedirectToAction("Index");
            }

            ViewBag.ID_LIBRERIA = new SelectList(db.CATALOGO_LIBRERIA, "ID_LIBRERIA", "ID_LIBRERIA", inventario_pdv.ID_LIBRERIA);
            ViewBag.ID_PDV = new SelectList(db.PUNTO_VENTA, "ID_PDV", "NOMBRE", inventario_pdv.ID_PDV);
            return View(inventario_pdv);
        }
        // POST api/InventarioPDVAPI
        public HttpResponseMessage PostINVENTARIO_PDV(int id_libreria, int id_pdv, int isbn, int cantidad_disponible)
        {
            INVENTARIO_PDV inventario_pdv = new INVENTARIO_PDV();
            inventario_pdv.ID_LIBRERIA = id_libreria;
            inventario_pdv.ID_PDV = id_pdv;
            inventario_pdv.ISBN = isbn;
            inventario_pdv.CANTIDAD_DISPONIBLE = cantidad_disponible;

            if (ModelState.IsValid)
            {
                db.INVENTARIO_PDV.Add(inventario_pdv);
                db.SaveChanges();

                HttpResponseMessage response = Request.CreateResponse(HttpStatusCode.Created, inventario_pdv);
                response.Headers.Location = new Uri(Url.Link("DefaultApi", new { id = inventario_pdv.ID_LIBRERIA }));
                return response;
            }
            else
            {
                return Request.CreateErrorResponse(HttpStatusCode.BadRequest, ModelState);
            }
        }
        // PUT api/InventarioPDVAPI/5
        public HttpResponseMessage PutINVENTARIO_PDV(int id, INVENTARIO_PDV inventario_pdv)
        {
            if (!ModelState.IsValid)
            {
                return Request.CreateErrorResponse(HttpStatusCode.BadRequest, ModelState);
            }

            if (id != inventario_pdv.ID_LIBRERIA)
            {
                return Request.CreateResponse(HttpStatusCode.BadRequest);
            }

            db.Entry(inventario_pdv).State = EntityState.Modified;

            try
            {
                db.SaveChanges();
            }
            catch (DbUpdateConcurrencyException ex)
            {
                return Request.CreateErrorResponse(HttpStatusCode.NotFound, ex);
            }

            return Request.CreateResponse(HttpStatusCode.OK);
        }
        // POST api/InventarioPDVAPI
        public HttpResponseMessage PostINVENTARIO_PDV(INVENTARIO_PDV inventario_pdv)
        {
            if (ModelState.IsValid)
            {
                db.INVENTARIO_PDV.Add(inventario_pdv);
                db.SaveChanges();

                HttpResponseMessage response = Request.CreateResponse(HttpStatusCode.Created, inventario_pdv);
                response.Headers.Location = new Uri(Url.Link("DefaultApi", new { id = inventario_pdv.ID_LIBRERIA }));
                return response;
            }
            else
            {
                return Request.CreateErrorResponse(HttpStatusCode.BadRequest, ModelState);
            }
        }