Hi Expert!

How to upload file in ASP.NET MVC 4. I'm try as following line of code. but it returns always null value. 

.cshtml

<input type="file" name="file" id="file" />

controller.cs

   [HttpPost]

    public ActionResult Index(BookModel model, HttpPostedFileBase file, FormCollection values)

    {

        try

        {

            if (!ModelState.IsValid)

            {

                return View("Index", new BookModel());

            }

            if (file != null && file.ContentLength > 0)

            {                    

                var fileName = Path.GetFileName(file.FileName);                    

                var path = Path.Combine(Server.MapPath("~/img/"), fileName);

                file.SaveAs(path);

                model.ImageUrl = fileName;

            }

         //SendMail();

        }

        catch (Exception ex)

        {               

            return View("Index", new BookModel());

        }

        return View("Success");

    }

Please help me. 

Thanks in advance!