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angular.js - angular作用域

今天学习指令，遇到了一些困惑：

    <!DOCTYPE html>
<html ng-app="app">
<head>
    <meta charset="utf-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <title></title>
    <link rel="stylesheet" href="../css/lib/bootstrap4.css">

    <script type="text/javascript" src='../js/lib/angular.js' ></script>
    <script type="text/javascript" src='js/scope2.js'></script>
</head>

<body>
    
    <p ng-init = 'someProperty="some date"'>
    
        <p ng-init='siblingProperty="moredata"'>
            Inside p Two : {{aThirdProperty}}
    
            <p ng-init="aThirdProperty='data for 3rd property'" ng-controller="someCtrl">
                Inside p Three:　{{aThirdProperty}}
    
                    <p ng-controller="secondCtrl">
                        Inside p Four:　{{aThirdProperty}}
                        <br>
                        OutSide myDirective: {{myProperty}}
                        <p my-directive ng-init="myProperty='wow! that is cool'">
                            Inside myDirective : {{myProperty}}
                        </p>

                    </p>

            </p>

        </p>
    
    </p>
    
</body>
</html>

js

    var app = angular.module('app', []);
app.controller('someCtrl', ['$scope', function($scope){

    
}])

app.controller('secondCtrl', ['$scope', function($scope){
    console.log($scope.myProperty)    //undefined
    
}])
app.directive('myDirective',function(){
    return {
        restrict :'A',
        scope:false
        
    }

})

为什么打印出来的是undefined？

然后把js指令里的scope改为scope:{};为什么弹出来的是这个？就是说为什么外面的OutSide myDirective: wow! that is cool会有值？

    Inside p Two :
    Inside p Three:　data for 3rd property
    Inside p Four:　data for 3rd property 
    OutSide myDirective: wow! that is cool
    Inside myDirective : wow! that is cool
PHP中文网PHP中文网2744 days ago527

reply all(3)I'll reply

  • 过去多啦不再A梦

    过去多啦不再A梦2017-05-15 17:00:35

    <p my-directive ng-init="myProperty='wow! that is cool'">
    Inside myDirective : {{myProperty}}
</p>

    First of all, what you wrote has little to do with instructions. The scope of the instruction's scope是影响它的template is not here. 

    app.controller('secondCtrl', ['$scope', function($scope){
    console.log($scope.myProperty)    //undefined
}])

    The reason for undefined here is because the controller is executed before ng-init. You can use delay or $watchmonitor

    $timeout(function() {
  console.log($scope.myProperty)
});
// or
$scope.$watch('myProperty', function(newVal) {
  console.log($scope.myProperty)
})

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    0
  • 阿神

    阿神2017-05-15 17:00:35

    Well,,, I understand the undefined above, but I am still a little confused about the latter one, that is to say, when scope:{}时，Inside myDirective : {{myProperty}}这个表达式还是属于外面那个作用域是不是？而此时template里面并没有设定，，，所以隔离作用域就没有起作用，我这样理解对吗？
    还有一个问题，既然这样，，，那为什么如果把scope设定为scope:true is the following result: 

        Inside p Two :
    Inside p Three:　data for 3rd property
    Inside p Four:　data for 3rd property 
    OutSide myDirective:
    Inside myDirect33ive : wow! that is cool

    Can you give me some more advice? Thank you~~

    reply
    0
  • PHP中文网

    PHP中文网2017-05-15 17:00:35

    scope true is an independent and isolated scope
    {}, only the properties inside {} will be isolated

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    0
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