ngModel是否在不使用“香蕉"的情况下创建双向数据绑定?包装纸 [英] does ngModel create two way data binding if used without "banana" wrapping

问题描述

在本文中 Todd Motto解释说:

In this article Todd Motto explains that:

ngModel =如果未分配绑定或值，则ngModel将寻找 名称属性，并将该值作为新的对象键分配给全局 ngForm对象:

ngModel = if no binding or value is assigned, ngModel will look for a name attribute and assign that value as a new Object key to the global ngForm Object:

<form novalidate #f="ngForm">
  ...
    <input
     type="text"
     placeholder="Your full name"
     ngModel>
  ...
</form>

关于香蕉"包装:

[(ngModel)] =双向绑定语法，可以从 绑定的组件类，但还要对其进行更新:

[(ngModel)] = two-way binding syntax, can set initial data from the bound component class, but also update it:

<form #f="ngForm">
  ...
    <input
      type="text"
      placeholder="Your full name"
      name="name"
      [(ngModel)]="user.name">
  ...
</form>

因此，我期望在他的最后一个示例中看到[(ngModel)].但是，他使用了普通的ngModel指令.它会创建双向数据绑定吗?看来它根本不会创建任何绑定.

So I was expecting to see [(ngModel)] used in his final example. However, he used the plain ngModel directive. Does it create two-way data-binding? It seems that it doesn't create any binding at all.

推荐答案

它创建了一种绑定到form.value[name]的方式，在这种情况下，ngModel只是更新了表单value对象中的相应属性.

It creates one way binding to form.value[name], ngModel in this case just updates corresponding property in forms value object.

请参见 https://angular.io/docs/ts/latest/api/forms/index/NgModel-directive.html

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