javascript - AngularJS ngModelController 基本问题

Question

在 ngModelController 示例的 Angular 文档中，javascript 文件说:

angular.module('customControl', []).
    directive('contenteditable', function() {
        return {
            restrict: 'A', // only activate on element attribute
            require: '?ngModel', // get a hold of NgModelController
            ...

为什么“ngModel”指的是 NgModelController？为什么不呢，"require: '?ngModelController"从命名的 Angular 来看似乎更合适。

此外，使用 $setViewValue() 函数更新模型与使用 $watch() 函数监视指令范围内模型的变化有什么区别？

谢谢!

Answer 1

Why does "ngModel" refers to the NgModelController? Why isn't it, "require: '?ngModelController" That seems more appropriate from a naming perspective.

因为 require 属性用于要求 controller 指令。例如，ngModel 指令有一个 controller 属性，该属性具有 $setViewValue 和一些其他函数。如果你正在制作一个自定义指令，你可以为它创建一个 Controller ，然后其他指令可以通过说 require: '?yourDirective' 或 require: '^yourDirective' 来访问它> 或 require: 'yourDirective'。

来自 Angular 文档:

controller - Controller constructor function. The controller is instantiated before the pre-linking phase and it is shared with other directives if they request it by name (see require attribute). This allows the directives to communicate with each other and augment each other's behavior.

和

require - Require another controller be passed into current directive linking function. The require takes a name of the directive controller to pass in. If no such controller can be found an error is raised.

您可以阅读更多here .