How can I pass variables between controllers?

One way to share variables across multiple controllers is to create a service and inject it in any controller where you want to use it.

Simple service example:

angular.module('myApp', [])
    .service('sharedProperties', function () {
        var property = 'First';

        return {
            getProperty: function () {
                return property;
            },
            setProperty: function(value) {
                property = value;
            }
        };
    });

Using the service in a controller:

function Ctrl2($scope, sharedProperties) {
    $scope.prop2 = "Second";
    $scope.both = sharedProperties.getProperty() + $scope.prop2;
}

This is described very nicely in this blog (Lesson 2 and on in particular).

I've found that if you want to bind to these properties across multiple controllers it works better if you bind to an object's property instead of a primitive type (boolean, string, number) to retain the bound reference.

Example: var property = { Property1: 'First' }; instead of var property = 'First';.

UPDATE: To (hopefully) make things more clear here is a fiddle that shows an example of:

• Binding to static copies of the shared value (in myController1)
  • Binding to a primitive (string)
  • Binding to an object's property (saved to a scope variable)
• Binding to shared values that update the UI as the values are updated (in myController2)
  • Binding to a function that returns a primitive (string)
  • Binding to the object's property
  • Two way binding to an object's property

--- I know this answer is not for this question, but I want people who reads this question and want to handle Services such as Factories to avoid trouble doing this ----

For this you will need to use a Service or a Factory.

The services are the BEST PRACTICE to share data between not nested controllers.

A very very good annotation on this topic about data sharing is how to declare objects. I was unlucky because I fell in a AngularJS trap before I read about it, and I was very frustrated. So let me help you avoid this trouble.

I read from the "ng-book: The complete book on AngularJS" that AngularJS ng-models that are created in controllers as bare-data are WRONG!

A $scope element should be created like this:

angular.module('myApp', [])
.controller('SomeCtrl', function($scope) {
  // best practice, always use a model
  $scope.someModel = {
    someValue: 'hello computer'
  });

And not like this:

angular.module('myApp', [])
.controller('SomeCtrl', function($scope) {
  // anti-pattern, bare value
  $scope.someBareValue = 'hello computer';
  };
});

This is because it is recomended(BEST PRACTICE) for the DOM(html document) to contain the calls as

<div ng-model="someModel.someValue"></div>  //NOTICE THE DOT.

This is very helpful for nested controllers if you want your child controller to be able to change an object from the parent controller....

But in your case you don't want nested scopes, but there is a similar aspect to get objects from services to the controllers.

Lets say you have your service 'Factory' and in the return space there is an objectA that contains objectB that contains objectC.

If from your controller you want to GET the objectC into your scope, is a mistake to say:

$scope.neededObjectInController = Factory.objectA.objectB.objectC;

That wont work... Instead use only one dot.

$scope.neededObjectInController = Factory.ObjectA;

Then, in the DOM you can call objectC from objectA. This is a best practice related to factories, and most important, it will help to avoid unexpected and non-catchable errors.

I like to illustrate simple things by simple examples :)

Here is a very simple Service example:

angular.module('toDo',[])

.service('dataService', function() {

  // private variable
  var _dataObj = {};

  this.dataObj = _dataObj;
})

.controller('One', function($scope, dataService) {
  $scope.data = dataService.dataObj;
})

.controller('Two', function($scope, dataService) {
  $scope.data = dataService.dataObj;
});

And here the jsbin

And here is a very simple Factory example:

angular.module('toDo',[])

.factory('dataService', function() {
  var _dataObj = {};
  return {
    dataObj: _dataObj
  };
})

.controller('One', function($scope, dataService) {
  $scope.data = dataService.dataObj;
})

.controller('Two', function($scope, dataService) {
  $scope.data = dataService.dataObj;
});

And here the jsbin

If that is too simple, here is a more sophisticated example

Also see the answer here for related best practices comments

Solution without creating Service, using $rootScope:

To share properties across app Controllers you can use Angular $rootScope. This is another option to share data, putting it so that people know about it.

The preferred way to share some functionality across Controllers is Services, to read or change a global property you can use $rootscope.

var app = angular.module('mymodule',[]);
app.controller('Ctrl1', ['$scope','$rootScope',
  function($scope, $rootScope) {
    $rootScope.showBanner = true;
}]);

app.controller('Ctrl2', ['$scope','$rootScope',
  function($scope, $rootScope) {
    $rootScope.showBanner = false;
}]);

Using $rootScope in a template (Access properties with $root):

<div ng-controller="Ctrl1">
    <div class="banner" ng-show="$root.showBanner"> </div>
</div>

The sample above worked like a charm. I just did a modification just in case I need to manage multiple values. I hope this helps!

app.service('sharedProperties', function () {

    var hashtable = {};

    return {
        setValue: function (key, value) {
            hashtable[key] = value;
        },
        getValue: function (key) {
            return hashtable[key];
        }
    }
});

If you don't want to make service then you can do like this.

var scope = angular.element("#another ctrl scope element id.").scope();
scope.plean_assign = some_value;

Ah, have a bit of this new stuff as another alternative. It's localstorage, and works where angular works. You're welcome. (But really, thank the guy)

https://github.com/gsklee/ngStorage

Define your defaults:

$scope.$storage = $localStorage.$default({
    prop1: 'First',
    prop2: 'Second'
});

Access the values:

$scope.prop1 = $localStorage.prop1;
$scope.prop2 = $localStorage.prop2;

Store the values

$localStorage.prop1 = $scope.prop1;
$localStorage.prop2 = $scope.prop2;

Remember to inject ngStorage in your app and $localStorage in your controller.

You could do that with services or factories. They are essentially the same apart for some core differences. I found this explanation on thinkster.io to be the easiest to follow. Simple, to the point and effective.

http://www.thinkster.io/angularjs/9jfpSmbx1j/angularjs-sharing-data-between-controllers

Couldn't you also make the property part of the scopes parent?

$scope.$parent.property = somevalue;

I'm not saying it's right but it works.

I'd like to contribute to this question by pointing out that the recommended way to share data between controllers, and even directives, is by using services (factories) as it has been already pointed out, but also I'd like to provide a working practical example of how to that should be done.

Here is the working plunker: http://plnkr.co/edit/Q1VdKJP2tpvqqJL1LF6m?p=info

First, create your service, that will have your shared data:

app.factory('SharedService', function() {
  return {
    sharedObject: {
      value: '',
      value2: ''
    }
  };
});

Then, simply inject it on your controllers and grab the shared data on your scope:

app.controller('FirstCtrl', function($scope, SharedService) {
  $scope.model = SharedService.sharedObject;
});

app.controller('SecondCtrl', function($scope, SharedService) {
  $scope.model = SharedService.sharedObject;
});

app.controller('MainCtrl', function($scope, SharedService) {
  $scope.model = SharedService.sharedObject;
});

You can also do that for your directives, it works the same way:

app.directive('myDirective',['SharedService', function(SharedService){
  return{
    restrict: 'E',
    link: function(scope){
      scope.model = SharedService.sharedObject;
    },
    template: '<div><input type="text" ng-model="model.value"/></div>'
  }
}]);

Hope this practical and clean answer can be helpful to someone.

Besides $rootScope and services, there is a clean and easy alternative solution to extend angular to add the shared data:

in the controllers:

angular.sharedProperties = angular.sharedProperties || angular.extend(the-properties-objects);

This properties belong to 'angular' object, separated from the scopes, and can be shared in scopes and services.

1 benefit of it that you don't have to inject the object: they are accessible anywhere immediately after your defination!