ember.js - 在Ember.js的模板中，当您在#each block 中时，如何在父上下文中引用值？

Question

我在模板中遇到一种情况，我想在每个块内的父上下文中的值上使用if块。

编码:

App = Ember.Application.create({});

App.view = Ember.View.extend({
    foo: [1, 2, 3],
    bar: true
});

模板:

<script type="text/x-handlebars">
{{#view App.view}}
    {{#each foo}}
        {{#if bar}}
            {{this}}
        {{/if}}
    {{/each}}
{{/view}}
</script>

这是行不通的，因为每个循环中引用的名称的作用域是迭代元素。您如何在父级上下文中指代事物？

演示: http://jsfiddle.net/hekevintran/sMeyC/1/

Answer 1

我找到了更好的解决方案。
从Ember.js View Layer指南(http://emberjs.com/guides/understanding-ember/the-view-layer/):

Handlebars helpers in Ember may also specify variables. For example, the {{#with controller.person as tom}} form specifies a tom variable that descendent scopes can access. Even if a child context has a tom property, the tom variable will supersede it.

This form has one major benefit: it allows you to shorten long paths without losing access to the parent scope.

It is especially important in the {{#each}} helper, which provides a {{#each person in people}} form. In this form, descendent context have access to the person variable, but remain in the same scope as where the template invoked the each.

模板:

<script type="text/x-handlebars" >
    {{#view App.view}}
        {{#each number in view.foo}}
            {{#if view.bar}}
                {{number}}
            {{/if}}
        {{/each}}
    {{/view}}
</script>​

演示: http://jsfiddle.net/hekevintran/hpcJv/1/