blocks|key|56009|text|通过注入$rootScope并将函数作为$watch方法的第一个参数，可以向监视集添加任何表达式。伪代码：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|56010|$rootScope.$watch(function()+{
++return+//value+to+be+watched;
},+function+watchCallback(newValue,+oldValue)+{
++//react+on+value+change+here
});|code-block|syntax|javascript|56011|不要忘记第三个参数，即$watch方法的布尔参数。如果您想深入观察整个对象的更改，则需要指定true。|56012|entityMap^0|4|A|K|6|0|0|B|6|1A|4|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]|$9|R|A|S|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|T|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|U|8|@$9|V|A|W|B|C]|$9|X|A|Y|B|C]]|D|@]|E|$]]|$1|M|3|-4|5|6|7|Z|8|@]|D|@]|E|$]]]|N|$]]

You can add any expression to the set of watches by injecting the <code>$rootScope</code> and using a function a first argument to the <code>$watch</code> method. Pseudo-code:

<pre><code>$rootScope.$watch(function() {
 return //value to be watched;
}, function watchCallback(newValue, oldValue) {
 //react on value change here
});
</code></pre>

Don't forget about the third, Boolean argument to the <code>$watch</code> method. You need to specify <code>true</code> if you want to deep-watch an entire object for changes.

blocks|key|272565|text|服务本质上类似于类和内部方法。您可以设置一个方法，您可以从控制器调用该方法，该方法的参数是作用域并应用监视表达式：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|272566|app.service('myservice',function(){
++++this.listen+=+function($scope)+{
++++++++$scope.$watch(function(){return+someScopeValue},function(){
+++++++++++//$scope.dosomestuff();
++++++++});
++++}
});

//your+controller

function+myCtrl($scope,myservice)+{
++++$scope.listen+=+function()+{
++++++++myservice.listen($scope);
++++}

++++//call+your+method
++++$scope.listen();
}|code-block|syntax|javascript|272567|更新:如果您正在尝试查看服务中的私有局部变量，请参阅使用$rootScope的公认答案。如果你试图在一个局部作用域中$watch一个$scope变量，那么上面是你最好的选择。他们正在实现两个截然不同的目标。|272568|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

services by their very nature are like classes and house methods. You can set up a method which you call from your controller who's argument is the scope and applies a watch expression:

<pre><code>app.service('myservice',function(){
 this.listen = function($scope) {
 $scope.$watch(function(){return someScopeValue},function(){
 //$scope.dosomestuff();
 });
 }
});

//your controller

function myCtrl($scope,myservice) {
 $scope.listen = function() {
 myservice.listen($scope);
 }

 //call your method
 $scope.listen();
}
</code></pre>

update: If you are trying to watch a private local variable inside of a service, see the accepted answer using $rootScope. If you are trying to $watch a $scope variable within a local scope than the above is your best bet. They are achieving two very different things.

blocks|key|272609|text|嘿，刚刚有一个情况，我有一个相当大的手表设置在两个不同的控制器上。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|272610|因为我不想重复我刚刚定义的任何代码，以便在我的服务中运行：|272611|angular
++++.module('invoice')
++++.factory('invoiceState',+function+()+{
++++++++var+invoice+=+{
++++++++++++client_info:+{
++++++++++++++++lastname:+"",
++++++++++++++++firstname:+"",
++++++++++++++++email:+"",
++++++++++++++++phone:+"",
++++++++++++++++id_client:+"",
++++++++++++++++...+
+++++++++++++}
++++++++}
++++++++invoice.watchAccommodation+=+function+(newVal,+oldVal)+{
++++++++++++var+accommodation+=+newVal;
++++++++++++//Whatever+you+would+normally+have+in+your+watch+function
++++++++}|code-block|syntax|javascript|272612|然后，我可以在我注入了服务的任何控制器的监视中调用这个函数|272613|function+NewInvoiceCtrl(invoiceState)+{
++++$scope.$watch('invoice.accommodation',invoiceState.watchAccommodation,+true);
}|272614|我没有太多使用AngularJS的经验，所以我不能真正深入讨论这种方法的性能方面，但它是有效的;)|272615|entityMap^0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|R|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|S|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|T|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|U|8|@]|9|@]|A|$G|H]]|$1|M|3|N|5|6|7|V|8|@]|9|@]|A|$]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

Hey just had a situation where I had a pretty big watch setup on 2 different controllers.

As I didn't want to duplicate any code I just defined to function in my service :

<pre><code>angular
 .module('invoice')
 .factory('invoiceState', function () {
 var invoice = {
 client_info: {
 lastname: "",
 firstname: "",
 email: "",
 phone: "",
 id_client: "",
 ... 
 }
 }
 invoice.watchAccommodation = function (newVal, oldVal) {
 var accommodation = newVal;
 //Whatever you would normally have in your watch function
 }
</code></pre>

Then I can just call this function in the watch of any controller into which I injected the service

<pre><code>function NewInvoiceCtrl(invoiceState) {
 $scope.$watch('invoice.accommodation',invoiceState.watchAccommodation, true);
}
</code></pre>

I do not have much experience with AngularJS so I can't really go into the performance aspects of this approach but it works ;)

Is it possible to set up a <code>$watch</code> on an array of objects inside a service (I'd like the <code>$watch</code> declaration itself to be inside the service)?

$watch inside a service?

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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是否可以在服务内的对象数组上设置$watch (我希望$watch声明本身位于服务内)？

问在服务中使用$watch？
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问在服务中使用$watch？
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