如果在没有“banana"的情况下使用，ngModel 是否会创建两种方式的数据绑定?包裹 [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 = 如果没有分配绑定或值，ngModel 将寻找一个name 属性并将该值作为新的 Object 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，可以从绑定组件类，同时更新它:

[(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>

所以我期待在他的最后一个例子中看到 [(ngModel)] .但是，他使用了普通的 ngModel 指令.它是否创建了双向数据绑定?似乎它根本没有创建任何绑定.

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

它创建一种方式绑定到 form.value[name]，ngModel 在这种情况下只是更新表单 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.

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

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