Microsoft Dot Net Master: AngularJS

Monday, March 9, 2015

AngularJS - Forms

AngularJS enriches form filling and validation. We can use ng-click event to handle the click button and use $dirty and $invalid flags to do the validation in a seamless way. Use novalidate with a form declaration to disable any browser-specific validation. The form controls make heavy use of AngularJS events. Let us have a look at the events first.

Events

AngularJS provides multiple events associated with the HTML controls. For example, ng-click directive is generally associated with a button. AngularJS supports the following events:

ng-click
ng-dbl-click
ng-mousedown
ng-mouseup
ng-mouseenter
ng-mouseleave
ng-mousemove
ng-mouseover
ng-keydown
ng-keyup
ng-keypress
ng-change

ng-click

Reset data of a form using on-click directive of a button.

<input name="firstname" type="text" ng-model="firstName" required>
<input name="lastname" type="text" ng-model="lastName" required>
<input name="email" type="email" ng-model="email" required>
<button ng-click="reset()">Reset</button>
<script>
   function studentController($scope) { 
      $scope.reset = function(){
         $scope.firstName = "Mahesh";
         $scope.lastName = "Parashar";
         $scope.email = "MaheshParashar@tutorialspoint.com";
  }   
   $scope.reset();
}
</script>

Validate Data

The following can be used to track error.

$dirty - states that value has been changed.
$invalid- states that value entered is invalid.
$error- states the exact error.

Example

The following example will showcase all the above-mentioned directives.

testAngularJS.htm

<html>
<head>
<title>Angular JS Forms</title>
<style>
table, th , td {
  border: 1px solid grey;
  border-collapse: collapse;
  padding: 5px;
}
table tr:nth-child(odd) {
  background-color: #f2f2f2;
}
table tr:nth-child(even) {
  background-color: #ffffff;
}
</style>
</head>
<body>
<h2>AngularJS Sample Application</h2>
<div ng-app="" ng-controller="studentController">
<form name="studentForm" novalidate>
<table border="0">
<tr><td>Enter first name:</td><td><input name="firstname" type="text" ng-model="firstName" required>
   <span style="color:red" ng-show="studentForm.firstname.$dirty && studentForm.firstname.$invalid">
      <span ng-show="studentForm.firstname.$error.required">First Name is required.</span>
   </span>
</td></tr>
<tr><td>Enter last name: </td><td><input name="lastname"  type="text" ng-model="lastName" required>
   <span style="color:red" ng-show="studentForm.lastname.$dirty && studentForm.lastname.$invalid">
      <span ng-show="studentForm.lastname.$error.required">Last Name is required.</span>
   </span>
</td></tr>
<tr><td>Email: </td><td><input name="email" type="email" ng-model="email" length="100" required>
<span style="color:red" ng-show="studentForm.email.$dirty && studentForm.email.$invalid">
      <span ng-show="studentForm.email.$error.required">Email is required.</span>
   <span ng-show="studentForm.email.$error.email">Invalid email address.</span>
   </span>
</td></tr>
<tr><td><button ng-click="reset()">Reset</button></td><td><button 
 ng-disabled="studentForm.firstname.$dirty && studentForm.firstname.$invalid ||
     studentForm.lastname.$dirty && studentForm.lastname.$invalid ||
     studentForm.email.$dirty && studentForm.email.$invalid"
 ng-click="submit()">Submit</button></td></tr>
</table>
</form>
</div>
<script>
function studentController($scope) { 
   $scope.reset = function(){
  $scope.firstName = "Mahesh";
  $scope.lastName = "Parashar";
  $scope.email = "MaheshParashar@tutorialspoint.com";
   }   
   $scope.reset();
}
</script>
<script src="http://ajax.googleapis.com/ajax/libs/angularjs/1.2.15/angular.min.js"></script>
</body>
</html>

Output

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