public ActionResult AssignUsers(ProjectUserViewModel model) { UserProjectsHelper helper = new UserProjectsHelper(); foreach (var user in model.SelectedUsers) { if (!helper.IsUserOnProject(user, model.Project.Id)) { helper.AddUserToProject(user, model.Project.Id); } } foreach (var user in db.Users.ToList()) { if (!model.SelectedUsers.Contains(user.Id)) { helper.RemoveUserFromProject(user.Id, model.Project.Id); } } db.SaveChanges(); return(RedirectToAction("Index", "Projects", model)); }