Update: I have a new article on the new features of AngularJS validation using ng-message. Check it out here:
http://www.codeproject.com/Articles/992545/AngularJS-Validation
Introduction
I previously wrote about creating a simple CRUD application using AngularJS. The link is here: An Overview of an AngularJS Project. Now, I would like to add a validation layer to make sure data entered is valid. For this tip, I will only use some of my data for validation.
I'm going to use Visual Studio 2013 community version with some dependencies like AngularJS, Bootstrap and Jquery.
I have a live preview for you to look at, please click on this link to view:
http://tonyjen.github.io/AngularJSValidation/
Background
Validation was always difficult in a web application. Many times, frameworks need to be used for validating form values. Also, these frameworks often don't work across all browers. AngularJS comes with validation built in so now it's much easier to create validation that works across browers.
Here is a screen shot of what the validation feature is supposed to look like:
Using the Code
Form
To initialize the validation process, you should start with a form container like this:
<form name="tenantForm">
Now inside the form, you can take input controls and add validation logic to them.
In validation scenarios, we typically have a few main attributes we would like to validate. They are Required, Minimum, Maxium, Pattern, Email, Number, and URL.
Required
This attribute forces the form to be invalid if a required field is not entered.
<input type="text" required />
Minimum Length
This attribute requires a minimum of characters before input can be accepted.
<input type="text" ng-minlength=5 />
Maxium Length
This attribute allows a maxium length of character or validation will fail.
<input type="text" ng-maxlength=20 />
Pattern Matching
This feature allows for custom matching using Regex.
<input type="text" ng-pattern="[a-zA-Z]" />
Email Matching
Angular provides a custom email matching feature.
<input type="email" name="email" ng-model="user.email" />
Number
This requires input to be numeric format before validation.
<input type="number" name="age" ng-model="user.age" />
URL
This requires input to be in a link format before validation.
<input type="url" name="homepage" ng-model="user.url" />
Error Messages
After creating the input controls, we now need a place to display errors when validation fails. We first start with a container with error-container. Then, we will go through each error type and display the correct error text:
<div class="error-container"
ng-show="tenantForm.FirstName.$dirty && tenantForm.FirstName.$invalid">
<small class="text-danger"
ng-show="tenantForm.FirstName.$error.required">
Your name is required.
</small>
<small class="text-danger"
ng-show="tenantForm.FirstName.$error.minlength">
Your name is required to be at least 3 characters
</small>
<small class="text-danger"
ng-show="tenantForm.FirstName.$error.maxlength">
Your name cannot be longer than 20 characters
</small>
</div>
After adding form control with data properties and error message classes, the application will perform a validation in each input control and display any validation errors.
Putting It All Together
So after combining the input and validation parts of the form, the HTML would look like this:
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>Real Estate</title>
<link href="Content/bootstrap.css" rel="stylesheet" />
<link href="realEstateApp/site.css" rel="stylesheet" />
</head>
<body ng-app="realestateApp" class="ng-scope">
<div class="panel panel-default">
<div class="container" ng-controller="tenantsController" ngcloak>
<h1>Tenants</h1>
<div class="row">
<div>
<button class="btn btn-primary" ng-click="previousTenant()">
Previous
</button>
<button class="btn btn-primary" ng-click="nextTenant()">
Next
</button>
<button class="btn btn-success" ng-click="addTenant()">
Add
</button>
<button class="btn btn-danger" ng-click="deleteTenant()">
Delete
</button>
<br style="clear:both">
<br>
</div>
</div>
<form name="tenantForm" style="width: 500px">
<div class="row">
<div ng-repeat="tenant in tenant">
<div>
<label>First Name: </label>
<input type="text"
placeholder="First Name"
name="FirstName"
ng-model="tenant.FirstName"
ng-minlength=3
ng-maxlength=20 required />
</div>
<div class="error-container"
ng-show="tenantForm.FirstName.$dirty && tenantForm.FirstName.$invalid">
<small class="text-danger"
ng-show="tenantForm.FirstName.$error.required">
Your name is required.
</small>
<small class="text-danger"
ng-show="tenantForm.FirstName.$error.minlength">
Your name is required to be at least 3 characters
</small>
<small class="text-danger"
ng-show="tenantForm.FirstName.$error.maxlength">
Your name cannot be longer than 20 characters
</small>
</div>
<div>
<label>Home Phone:</label>
<input type="number"
placeholder="Home Phone"
name="HomePhone"
ng-model="tenant.HomePhone"
ng-minlength=7
ng-maxlength=10 required />
</div>
<div class="error-container"
ng-show="tenantForm.HomePhone.$dirty && tenantForm.HomePhone.$invalid">
<small class="text-danger"
ng-show="tenantForm.HomePhone.$error.required">
Your home phone is required.
</small>
<small class="text-danger"
ng-show="tenantForm.HomePhone.$error.minlength">
Your home phone is required to be at least 7 digits
</small>
<small class="text-danger"
ng-show="tenantForm.HomePhone.$error.maxlength">
Your home phone cannot be longer than 10 digits
</small>
<small class="text-danger"
ng-show="tenantForm.HomePhone.$error.number">
Your home phone cannot be characters
</small>
</div>
<div>
<label>Email:</label>
<input type="email"
placeholder="Email"
name="Email"
ng-model="tenant.Email"
required />
</div>
<div class="error-container"
ng-show="tenantForm.Email.$dirty && tenantForm.Email.$invalid">
<small class="text-danger"
ng-show="tenantForm.Email.$error.required">
Your email is required.
</small>
<small class="text-danger"
ng-show="tenantForm.Email.$error.email">
Your email is not valid
</small>
</div>
<div>
<label>Webpage:</label>
<input class="input-large"
type="url"
placeholder="Webpage"
name="Webpage"
ng-model="tenant.Webpage"
required />
</div>
<div class="error-container"
ng-show="tenantForm.Webpage.$dirty && tenantForm.Webpage.$invalid">
<small class="text-danger"
ng-show="tenantForm.Webpage.$error.required">
Your webpage is required.
</small>
<small class="text-danger"
ng-show="tenantForm.Webpage.$error.url">
Your webpage is not valid
</small>
</div>
</div>
</div>
</form>
</div>
</div>
<script src="Scripts/jquery-1.9.1.js"></script>
<script src="Scripts/angular.js"></script>
<script src="realEstateApp/realestateApp.js"></script>
<script src="realEstateApp/controllers/tenantsController.js"></script>
<script src="realEstateApp/services/tenantService.js"></script>
</body>
</html>
Validation using AngularJS is much simpler and more concise than using 3rd party jquery libraries. Now your application can have validation without a lot of pain involved. I have provided a sample of my application which validates some common attributes, you can extend it or try to create your own.
History
Hello, I'm a developer in the Orlando area. I enjoy playing basketball, golf and learning about new technologies. I have a passion in the web development space and hope to learn more about how to creating useful apps and more importantly share my knowledge with the community.
I'm available for freelance work, specializing in web applications.
You can reach me at tonyjen0905@gmail.com
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