public ActionResult GetRoles(string UserName)
        {
            if (!string.IsNullOrEmpty(UserName))
            {
                ApplicationUser user = db.Users.FirstOrDefault(n => n.UserName.Equals(UserName));

                this.Usermanager         = new UserManager <ApplicationUser>(new UserStore <ApplicationUser>(this.db));
                ViewBag.RolesForThisUser = Usermanager.GetRoles(user.Id);
                var userList = db.Users.OrderBy(n => n.UserName).ToList().Select(e => new SelectListItem()
                {
                    Text  = e.UserName,
                    Value = e.UserName
                });

                ViewBag.Users = userList;
            }

            return(View());
        }