Sunday, 26 April 2015

AngularJS Controllers



AngularJS controllers control the data of AngularJS applications.
AngularJS controllers are regular JavaScript Objects.

AngularJS Controllers:
AngularJS applications are controlled by controllers.
The ng-controller directive defines the application controller.
A controller is a JavaScript Object, created by a standard JavaScript object constructor.
<div ng-app="myApp" ng-controller="myCtrl">

First Name: 
<input type="text" ng-model="firstName"><br>
Last Name: 
<input type="text" ng-model="lastName"><br>
<br>
Full Name: 
{{firstName + " " + lastName}}

</div>

<script>
var app = angular.module('myApp', []);
app.controller('myCtrl', function($scope) {
    $scope.firstName = "Ravi";
    $scope.lastName = "Gupta";
});
</script>
Application explained:
The AngularJS application is defined by ng-app. The application runs inside a <div>.
The ng-controller directive defines a controller.
The myCtrl function is a JavaScript function.
AngularJS will invoke the controller with a $scope object.
In AngularJS, $scope is the application object (the owner of application variables and functions).
The controller creates two properties (variables) in the scope (firstName and lastName).
The ng-model directives bind the input fields to the controller properties (firstName and lastName).

Controller Methods:
The example above demonstrated a controller object with two properties: lastName and firstName.
A controller can also have methods (variables as functions):
<div ng-app="myApp" ng-controller="personCtrl">

First Name: 
<input type="text" ng-model="firstName"><br>
Last Name: 
<input type="text" ng-model="lastName"><br>
<br>
Full Name: 
{{fullName()}}

</div>

<script>
var app = angular.module('myApp', []);
app.controller('personCtrl', function($scope) {
    $scope.firstName = "Ravi";
    $scope.lastName = "Gupta";
    $scope.fullName = function() {
        return $scope.firstName + " " + $scope.lastName;
    }

});
</script>

Controllers In External Files:
In larger applications, it is common to store controllers in external files.
Just copy the code between the <script> tags into an external file named personController.js:
<div ng-app="myApp" ng-controller="personCtrl">

First Name: 
<input type="text" ng-model="firstName"><br>
Last Name: 
<input type="text" ng-model="lastName"><br>
<br>
Full Name: 
{{firstName + " " + lastName}}

</div>

<script src="personController.js"></script>

Another Example:
For the next example we will create a new controller file:
angular.module('myApp', []).controller('namesCtrl', function($scope) {
    $scope.names = [
        {name:'Ravi',country:'Norway'},
        {name:'Rahul',country:'Sweden'},
        {name:'Chandan',country:'Denmark'}
    ];
});
Save the file as namesController.js
And then use the controller file in an application:
<div ng-app="myApp" ng-controller="namesCtrl">

<ul>
  
<li ng-repeat="x in names">
    
{{ x.name + ', ' + x.country }}
  
</li>
</ul>

</div>

<script src="namesController.js"></script>


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