角度投掷实际上不是一个函数

Question

您好：我正在使用角度js进行长轮询，一切正常，直到我创建了一个getResponse函数 该计划涉及 a）主要（在底部） b）服务的构造函数 c）“着名的”getResponse，它是服务的一个功能 d）用于处理响应的简单控制台日志 e）作为循环的setPolling服务 f）设置响应，以响应服务 g）一个简单的指令

你能说出为什么抛出这个.getResponse不是一个函数 实际上是什么时候......？继承人的代码

var DbService = function($http, $window, $interval) {
    this.http_ = $http;
    this.interval_ = $interval;
    this.window_ = $window;
    this.db = null;
};

DbService.prototype.getResponse = function() {
    this.http_({
        method: 'get',
        url: 'dependencies/request.php',
        data: ""
        }).then(function successCallback(response) {
            this.setResponse(response);
        }, function errorCallback(response) {
            console.log("Err response");
    });
};

DbService.processResponse = function(response) {
    console.log(this.response_);
};

DbService.prototype.setPolling = function() {
    this.interval_(function(){
        console.log("Hi World!");
        this.response_ = this.getResponse();
        this.processResponse(this.response_);
    }, 10000);
};

DbService.prototype.setResponse = function(response) {
    this.response_ = response;
};

var informAction = function($scope, DbService) {
    return {
        restrict: 'C',
        link: function($scope, elem, attr, ctrl) {
            action = DbService.getResponse();
            $scope.consmensaje += "Accion: " + action.data['action'] + "\n";
        }
    };
};

var MainController = function($http, $window, $interval, DbService) {
    this.http_ = $http;
    this.window_ = $window;
    this.interval_ = $interval;
    this.DbService_ = DbService;
    console.log("Dentro de Controller");
    this.DbService_.setPolling();
};


function main() {
    console.log("Comenzando");
    var app = angular.module('consola', []);
    app.service('DbService', DbService);
    app.controller(
      'MainController',
      ['$scope', '$http', '$interval', 'DbService',
        MainController]);
    app.directive('informAction', ['$scope', 'DbService', informAction]);
}

main();