Update Topic in Web API with Repository

home-index.js

   // /ng-js/ng-modules/home-index.js
    angular
        .module("homeIndex", ["ngRoute"])
        .config(config)
        .controller("topicsController", topicsController)
        .controller("newTopicController", newTopicController)
        .controller("editTopicController", editTopicController);
    
    function config($routeProvider) {
        $routeProvider
            //Other routes left out for brevity
            .when("/edittopic/:topicId", {
                templateUrl: "/ng-js/ng-templates/editTopicView.html",
                controller: "editTopicController",
                controllerAs: "vm"
            })
            .otherwise({ redirectTo: "/" });
    };
   
   //Other controllers left out for brevity
   
   function editTopicController($http, $window, $routeParams) {
        var vm = this;

        var url = "/api/topics/" + $routeParams.topicId;
        $http.get(url)
            .success(function (result) {
                vm.topic = result[0];
            })
            .error(function () {
                alert('error/failed');
            })
            .then(function () {
                //Nothing
            });

        vm.update = function (id) {
            var updateUrl = "/api/topics/" + id;
            $http.put(updateUrl, vm.editTopic)
                .success(function (result) {
                    var editTopic = result.data;
                    //TODO: merge with existing topics
                    //alert("Thanks for your post");
                })
                .error(function () {
                    alert("Update is broken, go fix it!");
                })
                .then(function () {
                    $window.location = "#/";
                });
        };
    };

IMessageBoardRepository

        bool EditTopic(int id, Search newSearch);

MessageBoardRepository

        public bool EditTopic(int id, Search editTopic)
        {
            //var item = _ctx.Topics.FirstOrDefault(t => t.TopicId == id);
            //item(editTopic).State = EntityState.Modified;
            //return true;

            try
            {
                //...Not sure what to do here you can see I was playing around with 
                //...Isolating the topic and then updating it above, but that code was not
                //...Working out. I was getting an error that said (Method, Delegate or Event is required
            }
            catch
            {
                //...
            }
        }

TopicsController

        public HttpResponseMessage Put(int id,[FromBody]Search editTopic)
        {
            if (_repo.EditTopic(id, editTopic) && _repo.Save())
            {
                return Request.CreateResponse(HttpStatusCode.Created, editTopic);
            }
            return Request.CreateResponse(HttpStatusCode.BadRequest);
        }