我不明白为什么$ rootScope可以工作，但在这种情况下不能$ scope
[英]I don't understand why $rootScope works but not $scope in this case
问题描述
I have an angular app, that places ng-app within the <html> tag instead of the body, so that the angular scope would cover the <title> . 
我有一个角度应用程序，它将ng-app放在<html>标签而不是正文中，这样角度范围将覆盖<title> 。 However, from within the angular controller, the $scope variable is not able to output anything within the <title> but $rootScope is. 但是，在角度控制器中， $scope变量无法在<title>内输出任何内容，而$rootScope可以。 I don't understand why this is the case. 我不明白为什么会这样。 As far as I know, $scope is local to the controller and $rootScope is global. 据我所知， $scope是控制器本地的， $rootScope是全局的。 However, in this case, I ensured that the ng-app was placed in the <html> tag so that <title> would be covered. 但是，在这种情况下，我确保将ng-app放在<html>标记中，以便覆盖<title> 。 As far the ng-controller is concerned, I am not really specifying it anywhere within my html page. 就ng-controller而言，我并没有在html页面中的任何地方指定它。
<html ng-app="my-app">
<head>
<meta charset="utf-8">
<title>{{scopeVar}}</title>
Any hints? 有什么提示吗？
3 个解决方案
解决方案1
1 2016-10-31 11:34:04
As pointed out by @deceeze, the reason why $rootScope worked but $scope didn't was simply because when working with ui-router , the controller is tied to the ui-view . 正如@deceeze指出的那样，$ rootScope起作用但$ scope不能起作用的原因仅仅是因为在使用ui-router ，控制器绑定到ui-view 。 Hence, anything outside of that will not be covered by $scope . 因此， $scope不会覆盖任何超出此$scope 。 But $rootScope on the other hand is global, and that covers anything within ng-app . 但另一方面， $rootScope是全局的，它涵盖了ng-app 。
解决方案2
0 2016-10-31 10:37:14
<html ng-app="my-app" ng-controller="controller_name">
<head>
<meta charset="utf-8">
<title>{{scopeVar}}</title>
</head>
</html>
put your controller in <html> it will work with scope too.Because $scope is available in its controller and $rootScope is global to complete app. 将您的控制器放在<html>它也将与作用域一起工作。因为$ scope在其控制器中可用，而$ rootScope对于完成应用程序是全局的。
解决方案3
0 2016-10-31 11:35:00
Grateful , when you add "ng-app" tag Angular gives you the $rootScope. 感激不尽 ，当您添加“ ng-app”标签时，Angular会为您提供$ rootScope。 When you create a controller Angular gives you a $scope. 当您创建控制器时，Angular会给您一个$ scope。
Prefer to create small controllers and put then where you want. 最好创建小型控制器，然后放置在所需位置。 When you create small controllers, you can use $scope for each one. 创建小型控制器时，可以对每个控制器使用$ scope。 Below i created two controllers, one to handler de header and other to handle my body. 在下面，我创建了两个控制器，一个用于处理抬头，另一个用于处理我的身体。 The " scopeVar " variable will be available in controller1 . “ scopeVar ”变量将在controller1中可用。
<html ng-app="my-app">
<head ng-controller="controller1">
<meta charset="utf-8">
<title>{{scopeVar}}</title>
</head>
<body>
<div ng-controller="controller2">
</div>
</body>
</html>
BUT, if you want to communicate from your controller to $rootScope, don't use $rootScope.somevariable = 'foo'. 但是，如果要从控制器与$ rootScope通信，请不要使用$ rootScope.somevariable ='foo'。 Use $broadcast and $emmit services to do that. 使用$ broadcast和$ emmit服务可以做到这一点。 Ex.: 例如：
$rootScope.$broadcast('event name', 'foo');
In your RUN configuration for the app you can listen that: 在应用程序的RUN配置中，您可以收听：
$rootScope.$on('event name', function(param1){
// param1 will be 'foo'
// do something
});
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