blacai blacai - 2 months ago 8
AngularJS Question

Replace $scope with "'controller' as" syntax

I'm following this AngularJS+ASP.NET tutorial(http://www.asp.net/web-api/tutorials/hands-on-labs/build-a-single-page-application-(spa)-with-aspnet-web-api-and-angularjs) and they make use of the $scope, but I'm trying to replace it with the new syntax 'controller' as. (after checking AngularJs "controller as" syntax - clarification?)

What I did it's not working at the moment, because the page calls the $http.get inside the nextQuestion() function, but the view remains the same with just the title "loading question..."

My Code:

JS http://pastebin.com/RfngRuZD

var app = angular.module('QuizApp', [])

app.controller('QuizCtrl', ['$http', function ($http) {
this.answered = false;
this.title = "loading question...";
this.options = [];
this.correctAnswer = false;
this.working = false;

this.answer = function () {
return this.correctAnswer ? 'correct' : 'incorrect';
};

// GET
this.nextQuestion = function () {
this.working = true;
this.answered = false;
this.title = "loading question...";
this.options = [];

$http.get('/api/trivia').success(function (data, status, headers, config) {
this.options = data.options;
this.title = data.title;
this.answered = false;
this.working = false;
}).error(function (data, status, headers, config) {
this.title = "Oops... something went wrong.";
this.working = false;
});
};

// POST
this.sendAnswer = function (option) {
this.working = true;
this.answered = true;

$http.post('/api/trivia', { 'questionId': option.questionId, 'optionId': option.id }).success(function (data, status, headers, config) {
this.correctAnswer = (data === "true");
this.working = false;
}).error(function (data, status, headers, config) {
this.title = "Oops... something went wrong.";
this.working = false;
});
};
}]);


Index.cshtml http://pastebin.com/YmV1hwcU

@{
ViewBag.Title = "Play";
}

<div id="bodyContainer" ng-app="QuizApp">
<section id="content">
<div class="container">
<div class="row">
<div class="flip-container text-center col-md-12" ng-controller="QuizCtrl as quiz" ng-init="quiz.nextQuestion()">
<div class="back" ng-class="{flip: quiz.answered, correct: quiz.correctAnswer, incorrect: !quiz.correctAnswer}">

<p class="lead">{{quiz.answer()}}</p>
<p>
<button class="btn btn-info btn-lg next option" ng-click="quiz.nextQuestion()" ng-disabled="quiz.working">Next Question</button>
</p>
</div>
<div class="front" ng-class="{flip: quiz.answered}">
<p class="lead">{{quiz.title}}</p>
<div class="row text-center">
<button class="btn btn-info btn-lg option"
ng-repeat="option in quiz.options" ng-click="quiz.sendAnswer(option)" ng-disabled="quiz.working">
{{option.title}}
</button>
</div>
</div>
</div>
</div>
</div>
</section>
</div>

@section scripts{
@Scripts.Render("~/Scripts/angular.js")
@Scripts.Render("~/Scripts/app/quiz-controller.js")
}

Answer

You basically found the reason why using this isn't a very good idea in controllers. The this in your $http's success promise is not the this of the controller because this function gets executed in a different context. This wouldn't be an issue if you get $scope via the closure.

You can workaround that by defining a variable var that = this; and then use that instead.