Data Validation in ASP.NET MVC

Data Validation in ASP.NET MVC

In this article, we will learn how to implement data validations in the ASP.NET MVC application.

In our previous article, we have created an application that performs Create, Edit, Delete and Details operations that generate views for each of the operations.

We will create new class called Blog and will implement data validation in the class properties, which will display validation messages on the click of Save button without data, as shown below in the image below.

In the above image, we created a class named Blog with data validation through data Annotation.

DataAnnotations

ASP.NET MVC uses DataAnnotations attributes to implement validations. DataAnnotations includes built-in validation attributes for different validation rules, which can be applied to the properties of model class. ASP.NET MVC framework will automatically enforce these validation rules and display validation messages in the view.

The DataAnnotations attributes included in System.ComponentModel.DataAnnotations namespace. The following table lists DataAnnotations validation attributes.

Attribute	Description
Required	Indicates that the property is a required field
StringLength	Defines maximum length for string field
Range	Defines minimum and maximum value for a numeric field
RegularExpression	Speicifies the field value must match with speicified Regular expression
CreditCard Speci	Specifies that the specified field is a credit card number
CustomValidation	Specifies custom validation method to validate the field
EmailAddress	Validates with email address format
FileExtension	Validates with File extension
MaxLength	Specifies maximum length for a string field
MinLength	Sepcifies minimum length for a string field
Phone	Specifies that the field is  a phone number using regular expression for phone number

Implementing Validation to our Blog Class

Apply DataAnnotation attributes to the properties of our Blog class as shown below

Here, we have made the Title property of the blog class as compulsory by decorating it with Required attribute with error to be displayed in case of irregularities.

The DatePosted property is decorated with two attributes to make it compulsory and display in Calendar Date picker as shown below

Save the project and create a controller with scaffolding to generate the Create and Edit methods and View pages as shown below

Run the application and see that data validation is properly enforced by the system as can be seen below

The view page provides the ValidationMessage HTML helper method for error messages display as can be seen below

Thank you