没有ng-model，AngularJS选择不起作用 [英] AngularJS select doesn't work without ng-model

问题描述

有人知道为什么在AngularJS中没有ng-model时select选择器不起作用吗?

Does anyone know why in AngularJS, the select selector doesn't work without the ng-model?

<select ng-model="bla_bla" ng-options="obj.value as obj.key for obj in languages"/>
<select ng-options="obj.value as obj.key for obj in languages"/>

上面的第一行代码将起作用，而第二行则将不起作用. 为什么???

The first line of code above will work while the second one will not work. Why ???

谢谢！

推荐答案

在Angular应用程序中使用select标记会生成ng-select指令，该指令是HTML SELECT元素加上角度数据绑定.在Angular源代码中查找此select指令，以下是其link方法的前几行:

Using the select tag within an Angular app generates the ng-select directive, which is an HTML SELECT element plus angular data-binding. Looking in the Angular source for this select directive, here are the first few lines from its link method:

link: function(scope, element, attr, ctrls) {
    // if ngModel is not defined, we don't need to do anything
    if (!ctrls[1]) return;
    ...

因此，如果未定义ngModel，则它实际上是内置在框架中以中止链接directive的操作，因此不会发生绑定.

So it is actually built into the framework to abort linking the directive if ngModel is not defined, and so no binding takes place.

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