在 ng-repeat 中修改 Angular 范围内的对象 [英] Modifying objects within Angular Scope inside ng-repeat

问题描述

我正在使用 ng-repeat 在 HTML 中创建一个表单，以从范围内的对象生成表单元素.我还使用该对象生成 ng-repeat 之外的其他元素.

HTML 中的简化示例如下所示:

<div ng-controller="Ctrl"><div class="block1"><form ng-repeat="(key, value) in test"><label>{{key}}</label><input ng-model="value"/><p>{{value}}</p></表单>
<div class="block2"><p>{{test.a}}</p><p>{{test.b}}</p>

在 JS 中:

angular.module('App', []);功能Ctrl($范围){$scope.test = {a:"abc",b:定义"}}

在本例中，block2 中的文本被设置为test.a 和test.b 的初始值.循环内的输入值和

值也设置为初始值.

当我修改输入中的值时，ng-repeat 块内的 <p> 值会正确更新，但 <p> 标记在block2 更新失败.

为什么会出现这种行为?ng-repeat 是否创建了自己的隔离范围?如果是这样，我如何才能更新控制器级别的范围?另外，有人可以解释这种行为背后的想法以及它提供的任何优势吗?

JSFiddle 显示问题

解决方案

ng-repeat 为每个重复项创建一个子作用域.因此，您正在尝试将原语传递给子作用域，而该子作用域不会创建对父级的引用.但是，当您传递对象时，您传递的是原始对象引用.

来自 Angular 之父之一的口中:

<块引用>

在 ng-model 中总是有一个点

这是一个关于 Angular 最佳实践的精彩视频，由 Angular 创建者提供(2012/12/11).转到第 31 分钟，详细了解这种确切情况

将数据修改为对象数组:

$scope.test = [{ val:"abc",key:'a'}, {val:"def",key:'b'} ]

然后在中继器中:

<label>{{item.key}}</label><input ng-model="item.val"/><p>{{item.val}}</p></表单>

演示

I'm creating a form in HTML using ng-repeat to generate the form elements from an object in the scope. I also use that object to generate other elements outside of the ng-repeat.

A simplified example looks like this in HTML:

<div ng-app="App">
  <div ng-controller="Ctrl">
      <div class="block1">
          <form ng-repeat="(key, value) in test">
              <label>{{key}}</label>
              <input ng-model="value" />
              <p>{{value}}</p>
          </form>
      </div>
      <div class="block2">
        <p>
          {{test.a}}
        </p>
        <p>
            {{test.b}}
        </p>
      </div>
  </div>
</div>

and this in JS:

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

function Ctrl($scope) {
    $scope.test = {
        a:"abc",
        b:"def"
    }
}

In this example, the text in block2 is set to the initial values of test.a and test.b. The input values and <p> values inside of the loop are also set to the initial value.

When I modify the values within the inputs, the <p> values inside of the ng-repeat block update correctly, but the <p> tags in block2 fail to update.

Why is this the behavior? Does ng-repeat create its own isolated scope? If so how can I get the controller level scope to update? Also, could somebody explain the thinking behind this behavior and any advantages it provides?

JSFiddle Showing the problem

解决方案

ng-repeat creates a child scope for each repeated item. As a result you are trying to pass a primitive to child scope which won't create a reference to parent. When you pass objects however, you pass the original object reference.

From the mouth of one of the fathers of Angular:

Always have a dot in ng-model

This is a great video regarding Angular Best Practices given by Angular creator (2012/12/11). Go to minute 31 for well explained detail of this exact situation

Modify data to array of objects:

$scope.test = [{ val:"abc",key:'a'}, {val:"def",key:'b'} ]

Then in repeater:

<form ng-repeat="item in test">
  <label>{{item.key}}</label>
  <input ng-model="item.val" />
  <p>{{item.val}}</p>
</form>

DEMO

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