Main.Controllers.ManageController.ViewUser C# (CSharp) Method

        public ActionResult ViewUser(String user) {
            AspNetUser u = db.AspNetUsers.Where(m => m.Id == user).FirstOrDefault();

            ViewBag.UserID = User.Identity.Name;
            ViewBag.UserAvatar = db.AspNetUsers.Where(p => p.Id == user).FirstOrDefault().Avatar;

            ViewData["posts"] = db.Posts.Include(p => p.AspNetUser).Include(p => p.Category).Where(p => p.AspNetUser.Id == user).ToList();
            ViewData["comments"] = db.Comments.Include(p => p.AspNetUser).Where(p => p.AspNetUser.Id == user).ToList();

            return View(u);
        }

 public void testViewUser()
 {
     ManageController manageController = new ManageController();
     ActionResult viewUser = manageController.ViewUser("HaveNeed");
 }