Microsoft Dot Net Master: AngularJS

Monday, March 9, 2015

AngularJS - Views

AngularJS supports Single Page Application via multiple views on a single page. To do this, AngularJS has provided ng-view and ng-template directives, and $routeProvider services.

ng-view Directive

The ng-view directive simply creates a place holder where a corresponding view (HTML or ng-template view) can be placed based on the configuration.

Usage

Define a div with ng-view within the main module.

<div ng-app="mainApp">
...
   <div ng-view></div>

</div>

ng-template Directive

The ng-template directive is used to create an HTML view using script tag. It contains id attribute which is used by $routeProvider to map a view with a controller.

Usage

Define a script block with type as ng-template within the main module.

<div ng-app="mainApp">
...
   <script type="text/ng-template" id="addStudent.htm">
      <h2> Add Student </h2>
         {{message}}
   </script>

</div>

$routeProvider Service

The $routeProvider is a key service which sets the configuration of URLs, maps them with the corresponding HTML page or ng-template, and attaches a controller with the same.

Usage 1

Define a script block with type as ng-template within the main module.

<div ng-app="mainApp">
...
   <script type="text/ng-template" id="addStudent.htm">
      <h2> Add Student </h2>
         {{message}}
   </script>

</div>

Usage 2

Define a script block with main module and set the routing configuration.

 var mainApp = angular.module("mainApp", ['ngRoute']);
      
      mainApp.config(['$routeProvider',
         function($routeProvider) {
            $routeProvider.
               when('/addStudent', {
                  templateUrl: 'addStudent.htm',
                  controller: 'AddStudentController'
               }).
               when('/viewStudents', {
                  templateUrl: 'viewStudents.htm',
                  controller: 'ViewStudentsController'
               }).
               otherwise({
                  redirectTo: '/addStudent'
               });
         }]);

The following points are important to be considered in the above example:

$routeProvider is defined as a function under config of mainApp module using key as '$routeProvider'.
$routeProvider.when defines a URL "/addStudent", which is mapped to "addStudent.htm". addStudent.htm should be present in the same path as main HTML page. If the HTML page is not defined, then ng-template needs to be used with id="addStudent.htm". We used ng-template.
"otherwise" is used to set the default view.
"controller" is used to set the corresponding controller for the view.

Example

The following example shows the use of all the above-mentioned directives.

testAngularJS.htm

<html>
<head>
   <title>Angular JS Views</title>
   <script src="http://ajax.googleapis.com/ajax/libs/angularjs/1.2.15/angular.min.js"></script>
   <script src="http://ajax.googleapis.com/ajax/libs/angularjs/1.2.25/angular-route.min.js"></script>
</head>
<body>
   <h2>AngularJS Sample Application</h2>
   <div ng-app="mainApp">
      <p><a href="#addStudent">Add Student</a></p>
      <p><a href="#viewStudents">View Students</a></p>
      <div ng-view></div>
      <script type="text/ng-template" id="addStudent.htm">
         <h2> Add Student </h2>
         {{message}}
      </script>
      <script type="text/ng-template" id="viewStudents.htm">
         <h2> View Students </h2>     
         {{message}}
      </script> 
   </div>

   <script>
      var mainApp = angular.module("mainApp", ['ngRoute']);
      
      mainApp.config(['$routeProvider',
         function($routeProvider) {
            $routeProvider.
               when('/addStudent', {
                  templateUrl: 'addStudent.htm',
                  controller: 'AddStudentController'
               }).
               when('/viewStudents', {
                  templateUrl: 'viewStudents.htm',
                  controller: 'ViewStudentsController'
               }).
               otherwise({
                  redirectTo: '/addStudent'
               });
         }]);

         mainApp.controller('AddStudentController', function($scope) {
            $scope.message = "This page will be used to display add student form";
         });

         mainApp.controller('ViewStudentsController', function($scope) {
            $scope.message = "This page will be used to display all the students";
         });
   </script>
</body>
</html>

Output

Open the file testAngularJS.htm in a web browser and see the result.