如何使用Controller作为语法访问$ on，$ emit，$ broadcast方法?

问题描述

使用$scope可以很容易地发出事件或监视事件.

Using $scope it's easy to emit an event or watch for one.

(function() {
    "use strict";

    angular
        .module("app")
        .controller("Ctrl", [
            "$scope",
            CtrlDefinition
        ]);

    function CtrlDefinition($scope) {
        $scope.$on("change", listenForChange);

        function listenForChange(data) {
            //do something
        }
    }
})();

但是，如果我尝试使用var vm = this语法，则会警告$on，$emit和$broadcast不是this的方法.如何访问它们?我仍然需要在控制器定义中插入$scope吗?

But if I try to use var vm = this syntax, I'm warned that $on, $emit, and $broadcast are not methods of this. How can I access them? Do I still need to inject $scope in the controller definition?

(function() {
    "use strict";

    angular
        .module("app")
        .controller("Ctrl", CtrlDefinition);

    function CtrlDefinition() {
        var vm = this;
        vm.$on("change", listenForChange); //$on is not a method of vm
    }

})();

您可以做这样的事情，但这不会完全不必使用$scope的目的吗?

You could do something like this, but wouldn't it defeat the purpose of not having to use $scope at all?

(function() {
    "use strict";

    angular
        .module("app")
        .controller("Ctrl", [
            "$scope",
            CtrlDefinition
        ]);

    function CtrlDefinition($scope) {
        var vm = this;
        vm.scope = $scope;
        vm.scope.$on("change", listenForChange);
    }

})();

如何使用控制器作为语法访问观察者?

How can you access watchers with controller as syntax?

推荐答案

为了使用$scope上存在的任何内容，您不得不注入$scope.不幸的是，它很简单，这是"as"语法的缺点.

In order to use anything that exists on $scope, you are forced to inject $scope. It's unfortunately that straightforward, which is a shortcoming of the "as" syntax.

但是，好消息是，在this旁边插入$scope并不会改变控制器作为语法功能的方式，它只是使您能够访问驻留在$scope上的所有事件管理.

The good news however is that injecting $scope alongside this does not change how the controller as syntax functions, it simply gives you access to all of the event management that lives on $scope.

值得注意的是，这是Angular 2.0中出现问题的主要原因之一...存在一个实际问题，并且$scope与为解决范围问题而附加的"Controller as"语法之间存在差异在视图中.

It's worth noting that this is one of the primary reasons for what is coming in Angular 2.0...there is a real problem and discrepancy between $scope and the "Controller as" syntax that was bolted on to solve scoping issues in views.

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