为什么我的指令的选择没有绑定到控制器? [英] Why isn't my directive's selection being bound to the controller?

问题描述

我正在使用一个非常简单的指令 - 它是一个围绕下拉列表的小包装器.我想从中公开一个属性selectedOption"(好吧，selected-option)，我可以双向绑定到控制器.我已经在指令的范围内设置了属性(并将其设置为 = 我认为这将允许双向绑定)，然后在主控制器上公开一个属性.

我附上了一个例子.我原以为显示的默认项目是Beta".如果我将选择更改为 Alpha，则控制器值将更新为A".但这并没有发生 - 即使我已经指定该属性应该对控制器可用，它们似乎是孤立的.

我在这里遗漏了什么神奇的代码?

angular.module('app', []);angular.module('app').controller('test', function(){var vm = 这个；vm.inv = 'B';vm.displayInv = 函数 () {alert('inv:' + vm.inv);};});angular.module('app').directive('库存测试', 函数 () {返回 {限制:'E'，模板:'<select ng-model="ctrl.selectedOption" ng-options="inv.code as inv.desc for inv in ctrl.invTypes"></select>{{ctrl.sample}}.已选择:{{ctrl.selectedOption}}',范围:{selectedOption:'='}，控制器:函数(){this.invTypes = [{代码:'A'，描述:'阿尔法'}，{代码:'B'，描述:'Bravo'}，{代码:'C'，描述:'查理'}，];this.sample = '你好';},控制器为:'ctrl'}});

<script src="https://cdnjs.cloudflare.com/ajax/libs/angular.js/1.4.7/angular.js"></script><div ng-app="app" ng-controller="test as vm"><inventorytest selected-option='vm.inv'></inventorytest><button ng-click="vm.displayInv()">显示</button><br/>控制器:{{vm.inv}}

解决方案

默认情况下，Angular 创建一个 scope 对象(最常使用变量 $scope 引用)对于每个 HTML 模板.

代码中的 scope: { selectedOption: '='}, 实际上是为指令创建一个 isolated 作用域，并使 selectedOption> 该 scope 对象上的一个属性.

行 controllerAs: 'ctrl' 正在此相同的 scope 对象上创建一个属性，该对象指向控制器对象.

这实际上意味着在控制器中，您可以技术上访问ctrl.$parent.selectedOption，这将返回selectedOptionctrl 对象的父对象，即 scope.然而，在实践中，这非常麻烦.

在 Angular 1.3 中，添加了一个新选项，bindToController : true.此选项自动将 scope: 定义中的属性绑定到 controllerAs: 对象而不是 scope 本身.

I've got a very simple directive I'm working with - it's a small wrapper around a dropdown. I want to expose an attribute, "selectedOption" (well, selected-option) from it that I can two-way bind to the controller. I've set the property in the scope of the directive (and set it to = which I thought would allow the two-way binding), then exposed a property on the main controller.

I've attached an example. I would have expected that the default item shown would be "Beta". And if I changed selections to Alpha, the Controller value would be updated to "A". But that doesn't happen - they appear to be isolated even though I've specified that this property should be available to the controller.

What magic bit of code am I missing here?

angular
    .module('app', []);

angular.module('app').controller('test', function(){
    var vm = this;
    
    vm.inv = 'B';
    vm.displayInv = function () {        
        alert('inv:' + vm.inv);
    };
});

angular.module('app')
       .directive('inventorytest', function () {
    return {
        restrict: 'E',
        template: '<select ng-model="ctrl.selectedOption" ng-options="inv.code as inv.desc for inv in ctrl.invTypes"></select>{{ctrl.sample}}. Selected: {{ctrl.selectedOption}}',

        scope: { selectedOption: '='},
        controller: function () {
            this.invTypes = [
                { code: 'A', desc: 'Alpha' },
                { code: 'B', desc: 'Bravo' },
                { code: 'C', desc: 'Charlie' },
            ];
            this.sample = 'Hello';
        },
        controllerAs: 'ctrl'
    }
});

<script src="https://cdnjs.cloudflare.com/ajax/libs/angular.js/1.4.7/angular.js"></script>
<div ng-app="app" ng-controller="test as vm">
    <inventorytest selected-option='vm.inv'></inventorytest>
    <button ng-click="vm.displayInv()">Display</button>
    <br/>
    Controller: {{vm.inv}}
</div>

解决方案

By default, Angular creates a scope object (most commonly referred to with the variable $scope) for each HTML Template.

The scope: { selectedOption: '='}, in your code is actually creating an isolated scope for the directive, and making selectedOption a property on that scope object.

The line controllerAs: 'ctrl' is creating a property on this same scope object which points to the controller object.

This actually means that in the controller, you could technically access ctrl.$parent.selectedOption, which would return the selectedOption property of the ctrl object's parent, which is scope. In practice, however, this is very cumbersome.

In Angular 1.3, a new option was added, bindToController : true. This option automatically binds the properties from the scope: definition to the controllerAs: object instead of scope itself.

这篇关于为什么我的指令的选择没有绑定到控制器?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！