each line of above Register method that exist 'RoleManager' word I'm getting compile time error as below

[kelumKP]

   // POST: /Account/Register
    [HttpPost]
    [AllowAnonymous]
    [ValidateAntiForgeryToken]
    public async Task<ActionResult> Register(RegisterViewModel model, HttpPostedFileBase upload, params string[] selectedRoles)
    {

        try
        {
            if (ModelState.IsValid)
            {
                var user = new ApplicationUser { UserName = model.UserName, Email = model.Email };                      


                var result = await UserManager.CreateAsync(user, model.Password);

                if (result.Succeeded)
                {
                    //Add User to the selected Roles 
                    if (selectedRoles != null)
                    {
                        var addroles = await UserManager.AddToRolesAsync(user.Id, selectedRoles);
                        if (!addroles.Succeeded)
                        {
                            ModelState.AddModelError("", result.Errors.First());
                            ViewBag.RoleId = new SelectList(await RoleManager.Roles.ToListAsync("Name", "Name"));
                            return View();
                        }
                    }

                }

                else
                {
                    ModelState.AddModelError("", result.Errors.First());
                    ViewBag.RoleId = new SelectList(RoleManager.Roles, "Name", "Name");
                    return View();
                }

                return RedirectToAction("Index");
                // AddErrors(result);
            }

        }

        // If we got this far, something failed, redisplay form
        catch (RetryLimitExceededException /* dex */)
        {
            //Log the error (uncomment dex variable name and add a line here to write a log.
            ModelState.AddModelError("", "Unable to save changes. Try again, and if the problem persists see your system administrator.");
        }

        ViewBag.RoleId = new SelectList(RoleManager.Roles, "Name", "Name");

        return View(model);
    }

Using the generic type 'RoleManager' requires 2 type arguments

which means I'm getting 3 compile time errors in above method.