Event Handler in AngularJS
Angular JS
provide the event handler in HTML, which we can use to do operation, there are
following event which is provide by the Angular JS
AngularJS Events
You can add AngularJS event listeners to your HTML elements by
using one or more of these directives:
Ø
ng-blur
Ø
ng-change
Ø ng-click
Ø
ng-copy
Ø
ng-cut
Ø
ng-dblclick
Ø
ng-focus
Ø ng-keydown
Ø
ng-keypress
Ø
ng-keyup
Ø
ng-mousedown
Ø
ng-mouseenter
Ø ng-mouseleave
Ø
ng-mousemove
Ø
ng-mouseover
Ø
ng-mouseup
Ø
ng-paste
The event directives allows us to run AngularJS functions at certain
user events.
An AngularJS event will not overwrite an HTML event, both events
will be executed.
Mouse Events
Mouse events occur when the cursor moves over an element, in this
order:
Ø
ng-mouseenter
Ø
ng-mouseover
Ø
ng-mousemove
Ø
ng-mouseleave
Or when a mouse button is clicked on an element, in this order:
Ø
ng-mousedown
Ø
ng-mouseup
Ø
ng-click
You can add mouse events on any HTML element.
Some Angular
JS event we will here with an example
Ng-Click
Directive
The
ng-click directive
defines AngularJS code that will be executed when the element is being clicked.
1. Go to the visual studio and add
a project and right click on the solution and add a script file and give it
name as “Controller.js” and write the following code to this file
/// < sreference path="angular.min.js"
/>
var Myapp = angular
.module("MyModule", [])
.controller("myController", function ($scope) {
var technologies = [
{ name: "C#", likes: 0, dislikes: 0 },
{ name: "ASP.NET", likes: 0, dislikes: 0 },
{ name: "SQL", likes: 0, dislikes: 0 },
{ name: "AngularJS", likes: 0, dislikes: 0 }
];
$scope.technologies =
technologies;
$scope.incrementLikes = function (technology) {
technology.likes++;
};
$scope.incrementDislikes = function (technology) {
technology.dislikes++;
};
});
|
2. Now add a HTML
file to your solution and give it name as “Index.html” and write the following
code to this file
<!doctype html>
<html ng-app="MyModule">
<head>
<script src="Scripts/angular.min.js"></script>
<script src="Scripts/Controller.js"></script>
</head>
<body>
<div ng-controller="myController">
<table border="1" >
<thead>
<tr>
<th>Name</th>
<th>Likes</th>
<th>Dislikes</th>
<th>Like/Dislike</th>
</tr>
</thead>
<tbody>
<tr ng-repeat="technology in
technologies">
<td> {{ technology.name }} </td>
<td style="text-align:center"> {{ technology.likes }} </td>
<td style="text-align:center"> {{ technology.dislikes }} </td>
<td>
<input type="button" ng-click="incrementLikes(technology)" value="Like" />
<input type="button" ng-click="incrementDislikes(technology)" value="Dislike" />
</td>
</tr>
</tbody>
</table>
</div>
</body>
</html>
|
Index.html : Notice in the html below, we are associating incrementLikes() and incrementDislikes() functions with the respective button. When any of these
buttons are clicked, the corresponsing technology object is automatically
passed to the function, and the likes or dislikes property is incremented
depending on which button is clicked.
When
you will run application output will be like following
ng-mousemove directive
Increase
the count variable when the mouse moves over the button. Controller class will
be the same , there will be a little change in the Index.html,
Replace
the ng-click with the ng-mousemove and see the output, when you will take mouse
on the button increment and decrement will happen for respective button.
Index.html code
<!doctype html>
<html ng-app="MyModule">
<head>
<script src="Scripts/angular.min.js"></script>
<script src="Scripts/Controller.js"></script>
</head>
<body>
<div ng-controller="myController">
<table border="1" >
<thead>
<tr>
<th>Name</th>
<th>Likes</th>
<th>Dislikes</th>
<th>Like/Dislike</th>
</tr>
</thead>
<tbody>
<tr ng-repeat="technology in
technologies">
<td> {{ technology.name }} </td>
<td style="text-align:center"> {{ technology.likes }} </td>
<td style="text-align:center"> {{ technology.dislikes }} </td>
<td>
<input type="button" ng-mousemove ="incrementLikes(technology)" value="Like" />
<input type="button" ng-mousemove="incrementDislikes(technology)" value="Dislike" />
</td>
</tr>
</tbody>
</table>
</div>
</body>
</html>
|
Ng-show
directive
If you want to show a section of HTML code when a
button is clicked, and hide when the button is clicked again, like a dropdown
menu, make the button behave like a toggle switch:
Controller.JS Code
/// < reference path="angular.min.js"
/>
var Myapp = angular
.module("MyModule", [])
.controller("myController", function ($scope) {
$scope.showMe = false;
$scope.myFunc = function () {
$scope.showMe =
!$scope.showMe;
}
});
|
Index.HTML codes
<!doctype html>
<html ng-app="MyModule">
<head>
<script src="Scripts/angular.min.js"></script>
<script src="Scripts/Controller.js"></script>
</head>
<body>
<div ng-controller="myController">
<button ng-click="myFunc()">Click</button>
<div ng-show="showMe">
<h1>Technologies:</h1>
<div>C#</div>
<div>Asp.net</div>
<div>Angular JS</div>
</div>
</div>
<p>Click the button to
show/hide the menu.</p> </body>
</html>
|
Now run your application and click on button and
see the output
The
showMe variable starts out as the Boolean value false.
The
myFunc function sets the showMe variable to the opposite of what it is, by
using the ! (not) operator.
Ng-Hide
Just opposite of ng-show this ng-hide work, in above example (ng-show
example) replace the
ng-show with the ng-hide and see the output
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