如何从ember的子组件范围访问父组件范围？

debugcn 发表于 Dev

大卫·尼尔森

我很好奇这在炭烬中是否有可能。这是很容易做到的角度（plunkr：http : //plnkr.co/edit/O2e0ukyXdKMs4FcgKGmX?p=preview ）：

目标是为api使用者提供易于使用的，通用的，可重用的手风琴api。

我希望调用者能够使用的api是这样的（就像有角度的api一样）：

{{#ember-accordion listOfAccordionPaneObjects=model}}

  {{#ember-accordion-heading}}
     heading template html {{accordionPaneObject.firstName}}
  {{/ember-accordion-heading}}

  {{#ember-accordion-body}}
     this is the accordion body  {{accordionPaneObject.lastName}}
  {{/ember-accordion-body}}

{{/ember-accordion}}

这是我使用angular编写的一个工作示例：

<!doctype html>
<html ng-app="angular-accordion">
<head>
    <style>
        .angular-accordion-header {
            background-color: #999;
            color: #ffffff;
            padding: 10px;
            margin: 0;
            line-height: 14px;
            -webkit-border-top-left-radius: 5px;
            -webkit-border-top-right-radius: 5px;
            -moz-border-radius-topleft: 5px;
            -moz-border-radius-topright: 5px;
            border-top-left-radius: 5px;
            border-top-right-radius: 5px;
            cursor: pointer;
            text-decoration: none;
            font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
            font-size: 14px;
        }

        .angular-accordion-container {
            height: 100%;
            width: 100%;
        }

        .angular-accordion-pane {
            padding: 2px;
        }

        .angularaccordionheaderselected {
            background-color: #bbb;
            color: #333;
            font-weight: bold;
        }

        .angular-accordion-header:hover {
            text-decoration: underline !important;
        }

        .angularaccordionheaderselected:hover {
            text-decoration: underline !important;
        }

        .angular-accordion-pane-content {
            padding: 5px;
            overflow-y: auto;
            border-left: 1px solid #bbb;
            border-right: 1px solid #bbb;
            border-bottom: 1px solid #bbb;
            -webkit-border-bottom-left-radius: 5px;
            -webkit-border-bottom-right-radius: 5px;
            -moz-border-radius-bottomleft: 5px;
            -moz-border-radius-bottomright: 5px;
            border-bottom-left-radius: 5px;
            border-bottom-right-radius: 5px;
        }

        .angulardisabledpane {
            opacity: .2;
        }
    </style>
</head>
<body style="margin: 0;">


<div style="height: 90%; width: 100%; margin: 0;" ng-controller="outerController">

    <angular-accordion list-of-accordion-pane-objects="outerControllerData">
        <pane>
            <pane-header>Header {{accordionPaneObject}}</pane-header>
            <pane-content>Content {{accordionPaneObject}}</pane-content>
        </pane>
    </angular-accordion>

</div>

    <script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.1/angular.js"></script>
    <script>
        angular.module('angular-accordion', [])
                .directive('angularAccordion', function() {
                    var template = '';

                    return {
                        restrict: 'E',
                        transclude: true,
                        replace: true,
                        template: '<div>' +
                                        '<div ng-transclude class="angular-accordion-container" ng-repeat="accordionPaneObject in listOfAccordionPaneObjects"></div>' +
                                  '</div>',
                        controller: ['$scope', function($scope) {
                            var panes = [];

                            this.addPane = function(pane) {
                                panes.push(pane);
                            };
                        }],
                        scope: {
                            listOfAccordionPaneObjects: '='
                        }
                    };
                })
                .directive('pane', function() {
                    return {
                        restrict: 'E',
                        transclude: true,
                        replace: true,
                        template: '<div ng-transclude class="angular-accordion-pane"></div>'
                    };
                })
                .directive('paneHeader', function() {
                    return {
                        restrict: 'E',
                        require: '^angularAccordion',
                        transclude: true,
                        replace: true,
                        link: function(scope, iElement, iAttrs, controller) {
                            controller.addPane(scope);

                            scope.toggle = function() {
                                scope.expanded = !scope.expanded;
                            };
                        },
                        template: '<div ng-transclude class="angular-accordion-header" ng-click="toggle()"></div>'
                    };
                })
                .directive('paneContent', function() {
                    return {
                        restrict: 'EA',
                        require: '^paneHeader',
                        transclude: true,
                        replace: true,
                        template: '<div ng-transclude class="angular-accordion-pane-content" ng-show="expanded"></div>'
                    };
                })
                .controller('outerController', ['$scope', function($scope) {
                    $scope.outerControllerData = [1, 2, 3];
                }]);
    </script>
</body>
</html>

这就是我坚持使用余烬做同样的事情的地方：

index.html

<!DOCTYPE html>
<html>
    <body>
        <script src="//cdnjs.cloudflare.com/ajax/libs/require.js/2.1.9/require.js" data-main="main.js"></script>
    </body>
</html>

main.js

require.config({
    paths: {
        'ember': 'bower_components/ember/ember',
        'handlebars': 'bower_components/handlebars/handlebars',
        'jquery': 'bower_components/jquery/jquery',
        'text': 'bower_components/requirejs-text/text'
    },
    shim: {
        ember: {
            deps: ['jquery', 'handlebars'],
            exports: 'Ember'
        }
    }
});

define(function(require) {
    var Ember = require('ember'),
        EmberAccordionComponent = require('src/EmberAccordionComponent'),
        EmberAccordionTemplate = require('text!templates/ember-accordion.hbs'),
        EmberAccordionHeaderTemplate = require('text!templates/ember-accordion-header.hbs'),
        EmberAccordionBodyTemplate = require('text!templates/ember-accordion-body.hbs'),
        ApplicationTemplate = require('text!templates/application.hbs'),
        IndexTemplate = require('text!templates/index.hbs');

    var App = Ember.Application.create({
        LOG_STACKTRACE_ON_DEPRECATION : true,
        LOG_BINDINGS                  : true,
        LOG_TRANSITIONS               : true,
        LOG_TRANSITIONS_INTERNAL      : true,
        LOG_VIEW_LOOKUPS              : true,
        LOG_ACTIVE_GENERATION         : true
    });

    Ember.TEMPLATES = {};
    Ember.TEMPLATES['application'] = Ember.Handlebars.compile(ApplicationTemplate);
    Ember.TEMPLATES['index'] = Ember.Handlebars.compile(IndexTemplate);
    Ember.TEMPLATES['components/ember-accordion'] = Ember.Handlebars.compile(EmberAccordionTemplate);
    Ember.TEMPLATES['components/ember-accordion-header'] = Ember.Handlebars.compile(EmberAccordionHeaderTemplate);
    Ember.TEMPLATES['components/ember-accordion-body'] = Ember.Handlebars.compile(EmberAccordionBodyTemplate);

    App.EmberAccordionComponent = EmberAccordionComponent;

    App.IndexRoute = Ember.Route.extend({
        model: function() {
            return [
                {
                    name: 'Bob'
                },
                {
                    name: 'Jill'
                }]
        }
    })
});

EmberAccordionComponent.js

define(function(require) {
    require('ember');

    var EmberAccordionComponent = Ember.Component.extend({});

    return EmberAccordionComponent;
});

application.hbs

{{outlet}}

ember-accordion-header.hbs

<div style="color: blue;">
    {{yield}}
</div>

ember-accordion-body.hbs

<div style="color: green;">
    {{yield}}
</div>

index.hbs

{{#ember-accordion listOfAccordionPaneObjects=model}}
    {{#ember-accordion-header}}
        {{log this.constructor}}
        {{log this}}
        Header {{accordionPaneObject.name}}
    {{/ember-accordion-header}}
    {{#ember-accordion-body}}
        Body {{accordionPaneObject.name}}
    {{/ember-accordion-body}}
{{/ember-accordion}}

ember-accordion.hbs

{{#each accordionPaneObject in listOfAccordionPaneObjects}}
    {{yield}}
{{/each}}

这很难调试。因此输入：

{{log this.constructor}}

和：

{{log this}}

进入：

{{#ember-accordion-header}}

输出以下内容：

Class.model =未定义（为什么？）
Ember.ArrayController

我已尝试按照本文（http://www.thesoftwaresimpleton.com/blog/2013/11/21/component-block/）的建议重写Ember.Component的_yield私有方法：

var EmberAccordionHeaderComponent = Ember.Component.extend({
    _yield: function(context, options) {
        var get = Ember.get,
            view = options.data.view,
            parentView = this._parentView,
            template = get(this, 'template');

        if (template) {
            Ember.assert("A Component must have a parent view in order to yield.", parentView);
            view.appendChild(Ember.View, {
                isVirtual: true,
                tagName: '',
                _contextView: parentView,
                template: template,
                context: get(view, 'context'), // the default is get(parentView, 'context'),
                controller: get(view, 'controller'), // the default is get(parentView, 'context'),
                templateData: { keywords: parentView.cloneKeywords() }
            });
        }
    }
});

但是当我这样做时，我仍然无法在子组件范围内访问AccordionPaneObject，并且我的{{log this.constructor}}现在指向：.EmberAccordionHeaderComponent

因此，看来我要到达某个地方，我只需要再上一层。

当我尝试在EmberAccordionHeaderComponent.js中使用此代码时：

var EmberAccordionHeaderComponent = Ember.Component.extend({
    _yield: function(context, options) {
        var get = Ember.get,
            view = options.data.view,
            parentView = this._parentView,
            grandParentView = this._parentView._parentView,
            template = get(this, 'template');

        if (template) {
            Ember.assert("A Component must have a parent view in order to yield.", parentView);
            view.appendChild(Ember.View, {
                isVirtual: true,
                tagName: '',
                _contextView: parentView,
                template: template,
                context: get(grandParentView, 'context'), // the default is get(parentView, 'context'),
                controller: get(grandParentView, 'controller'), // the default is get(parentView, 'context'),
                templateData: { keywords: parentView.cloneKeywords() }
            });
        }
    }
});

我仍然无法访问AccordionPaneObject，但是现在我看到{{log this.constructor}}输出.EmberAccordionComponent。看来我在正确的范围内，但数据仍未绑定。

有趣的是，如果我在覆盖的_yield中使用了重新分配上下文和控制器的任何变体，则可以使用以下命令在控制台中访问所需的数据：

this._parentView._context.content

Marcio Junior

我用一些注释更新了您的代码，请看一下http://emberjs.jsbin.com/ivOyiZa/1/edit。

Java脚本

App = Ember.Application.create();

App.IndexRoute = Ember.Route.extend({
  model: function() {
    return [
      { head: "foo head", body: "foo body " },
      { head: "bar head", body: "bar body " },
      { head: "ya head", body: "yo body " }
    ];
  }
});

App.EmberAccordionComponent = Ember.Component.extend({
  // each accordion header/body item, will have a instance of that view.
  // so we can isolate the expanded state for each accordion header/body
  emberAccordionItemView: Ember.View.extend({    
    expanded: false
  }),
  _yield: function(context, options) {
    var get = Ember.get, 
    view = options.data.view,
    parentView = this._parentView,
    template = get(this, 'template');

    if (template) {
      Ember.assert("A Component must have a parent view in order to yield.", parentView);      
      view.appendChild(Ember.View, {
        isVirtual: true,
        tagName: '',
        _contextView: parentView,
        template: template,
        context: get(view, 'context'), // the default is get(parentView, 'context'),
        controller: get(view, 'controller'), // the default is get(parentView, 'context'),
        templateData: { keywords: parentView.cloneKeywords() }
      });
    }
  }
});

App.EmberAccordionHeaderComponent = Ember.Component.extend({  
  classNames: ['ember-accordion-header'],  
  click: function() {
    // here we toggle the emberAccordionItemView.expanded property
    this.toggleProperty('parentView.expanded');  
  }
});

范本

  <script type="text/x-handlebars" data-template-name="index">
    {{#ember-accordion listOfAccordionPaneObjects=model}}                        
          {{#ember-accordion-header}}
              {{head}} <!-- each object passed in listOfAccordionPaneObjects=model can be accessed here -->
          {{/ember-accordion-header}}
          {{#ember-accordion-body}}
              {{body}} <!-- each object passed in listOfAccordionPaneObjects=model can be accessed here -->
          {{/ember-accordion-body}}        
    {{/ember-accordion}}        
  </script>

  <script type="text/x-handlebars" data-template-name="components/ember-accordion">     
    {{#each listOfAccordionPaneObjects itemViewClass="view.emberAccordionItemView"}}            
      <div class="ember-accordion-container">
        <div class="ember-accordion-pane">          
            {{yield}}          
        </div>
      </div>      
    {{/each}}
  </script>

  <script type="text/x-handlebars" data-template-name="components/ember-accordion-header">        
    {{yield}}    
  </script>

  <script type="text/x-handlebars" data-template-name="components/ember-accordion-body">    
    <!-- when EmberAccordionHeaderComponent.click is called, the expanded property change and the content can be visible or not, based on expanded truth -->
    {{#if parentView.expanded}}
      <div class="ember-accordion-pane-content">
        {{yield}}
      </div>
    {{/if}}
  </script>

的CSS

.ember-accordion-header {
  background-color: #999;
  color: #ffffff;
  padding: 10px;
  margin: 0;
  line-height: 14px;
  -webkit-border-top-left-radius: 5px;
  -webkit-border-top-right-radius: 5px;
  -moz-border-radius-topleft: 5px;
  -moz-border-radius-topright: 5px;
  border-top-left-radius: 5px;
  border-top-right-radius: 5px;
  cursor: pointer;
  text-decoration: none;
  font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
  font-size: 14px;
}

.ember-accordion-container {
  height: 100%;
  width: 100%;
}

.ember-accordion-pane {
  padding: 2px;
}

.emberaccordionheaderselected {
  background-color: #bbb;
  color: #333;
  font-weight: bold;
}

.ember-accordion-header:hover {
  text-decoration: underline !important;
}

.emberaccordionheaderselected:hover {
  text-decoration: underline !important;
}

.ember-accordion-pane-content {
  padding: 5px;
  overflow-y: auto;
  border-left: 1px solid #bbb;
  border-right: 1px solid #bbb;
  border-bottom: 1px solid #bbb;
  -webkit-border-bottom-left-radius: 5px;
  -webkit-border-bottom-right-radius: 5px;
  -moz-border-radius-bottomleft: 5px;
  -moz-border-radius-bottomright: 5px;
  border-bottom-left-radius: 5px;
  border-bottom-right-radius: 5px;
}

.emberdisabledpane {
  opacity: .2;
}

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