In this article I will explain with an example, how to perform Aadhaar Number validation on Client Side using Data Annotation in ASP.Net MVC.
The Aadhaar Number validation will be performed using Regular Expression (Regex) in ASP.Net MVC.
 
 
Configuring Bundles and enabling Client Side validations
For more details, regarding how to configure Bundles and enable Client Side validation in ASP.Net MVC, please refer my article Using Bundles (ScriptBundle) in ASP.Net MVC Razor.
Note: By default, the validation done using Data Annotation attributes is Server Side. And hence to make it work Client Side, the Client Side validation must be enabled.
 
 
Model
The following Model class consists of one property AadhaarNumber. The property is decorated with the following Data Annotation attributes for performing validations.
1. Required Data Annotation attribute.
2. RegularExpression Data Annotation attribute.
Note: The Data Annotations attributes can be used with the Entity Data Model (EDM), LINQ to SQL, and other data models.
 
The Required Data Annotation and the RegularExpression Data Annotation attributes have been specified with a property ErrorMessage with a string value. As the name suggests, this string value will be displayed to the user when the respective validation fails.
The RegularExpression Data Annotation attribute has been set with a Regular Expression for validating Aadhaar Number.
The following Aadhaar Number formats will be termed as valid.
1. 12 digits without space. Ex: 123456789012
2. White space after every 4th digit. Ex: 1234 5678 9012
3. Hyphen (-) after every 4th digit. Ex: 1234-5678-9012
using System.ComponentModel.DataAnnotations;
 
namespace Aadhaar_Number_Validation_MVC.Models
{
    public class PersonModel
    {
        [Display(Name = "Aadhaar Number:")]
        [Required(ErrorMessage = "Aadhaar Number is required.")]
        [RegularExpression(@"^([0-9]{4}[0-9]{4}[0-9]{4}$)|([0-9]{4}\s[0-9]{4}\s[0-9]{4}$)|([0-9]{4}-[0-9]{4}-[0-9]{4}$)", ErrorMessage = "Invalid Aadhaar Number.")]
        public string AadhaarNumber { get; set; }
    }
}
 
 
Controller
The Controller consists of following two Action methods.
Action method for handling GET operation
Inside this Action method, simply the View is returned.
 
Action method for handling POST operation
This Action method handles the POST operation and when the form is submitted, the object of the PersonModel class is sent to this method.
The state of the submitted Model is checked using ModelState.IsValid property.
Note: ModelState.IsValid property is an inbuilt property which verifies two things:
1. Whether the Form values are bound to the Model.
2. All the validations specified inside Model class using Data annotations have been passed.
 
public class HomeController : Controller
{
    // GET: Home
    public ActionResult Index()
    {
        return View();
    }
 
    [HttpPost]
    public ActionResult Index(PersonModel person)
    {
        if (ModelState.IsValid)
        {
            // Validation success.
        }
 
        return View();
    }
}
 
 
View
Inside the View, in the very first line the PersonModel class is declared as Model for the View.
The Form
The View consists of an HTML Form which has been created using the Html.BeginForm method with the following parameters.
ActionName – Name of the Action. In this case the name is Index.
ControllerName – Name of the Controller. In this case the name is Home.
FormMethod – It specifies the Form Method i.e. GET or POST. In this case it will be set to POST.
 
Implementing Validation
The Form consists of the following three HTML Helper functions:-
1. Html.LabelFor – Displaying the Model property name.
2. Html.TextBoxFor – Creating a TextBox for the Model property.
3. Html.ValidationMessageFor – Displaying the Validation message for the property.
There is also a Submit button which when clicked, the Form gets submitted and the Aadhaar Number value is sent to the Controller.
 
Enabling Client-Side validations
By default, the validations performed using Data Annotations and Model class is performed on Server Side.
In order to enable Client-Side validations, you will need to render the following script bundles at the end of the Model using the Scripts.Render function.
1. jQuery
2. jQuery Validation
Once, the above files are rendered automatically, the Client-Side validations using Data Annotations is enabled.
@model Aadhaar_Number_Validation_MVC.Models.PersonModel
 
@{
    Layout = null;
}
 
<!DOCTYPE html>
 
<html>
<head>
    <meta name="viewport" content="width=device-width" />
    <title>Index</title>
    <style type="text/css">
        body { font-family: Arial; font-size: 10pt; }
        .error { color: red; }
    </style>
</head>
<body>
    @using (Html.BeginForm("Index", "Home", FormMethod.Post))
    {
        @Html.LabelFor(m => m.AadhaarNumber)
        @Html.TextBoxFor(m => m.AadhaarNumber, "")
        @Html.ValidationMessageFor(m => m.AadhaarNumber, "", new { @class = "error" })
        <hr />
        <input type="submit" value="Submit" />
    }
</body>
@Scripts.Render("~/bundles/jquery")
@Scripts.Render("~/bundles/jqueryval")
</html>
 
 
Screenshot
ASP.Net MVC: Client Side Aadhaar Number validation using Data Annotations
 
 
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