public IHttpActionResult PostProduct(Product product)
        {
            if (!ModelState.IsValid)
            {
                return BadRequest(ModelState);
            }

            _db.Products.Add(product);
            _db.SaveChanges();

            return CreatedAtRoute("DefaultApi", new { id = product.Id }, product);
        }
        // PUT api/Products/5
        public IHttpActionResult PutProduct(int id, Product product)
        {
            if (!ModelState.IsValid)
            {
                return BadRequest(ModelState);
            }

            if (id != product.Id)
            {
                return BadRequest();
            }

            //_db.Entry(product).State = EntityState.Modified;
            _db.MarkAsModified(product);

            try
            {
                _db.SaveChanges();
            }
            catch (DbUpdateConcurrencyException)
            {
                if (!ProductExists(id))
                {
                    return NotFound();
                }
                else
                {
                    throw;
                }
            }

            return StatusCode(HttpStatusCode.NoContent);
        }
 public void MarkAsModified(Product item)
 {
     Entry(item).State = EntityState.Modified;
 }
 public void MarkAsModified(Product item)
 {
 }