Model Validation in ASP.NET MVC

Also you can validate the string length using model validation.
In the preceding, you cannot exceed 10 letters, although it should be a minimum of 5 letters. It is also important that a regular expressions be used to do some validations. Using regular expressions I ignore empty spaces and digits that the user may enter in the text box.

You can compare a user-entered password and re-enter password that are matched using this compare attribute.
Using “DisplayFormat” you can specify the data format that should be displayed. For example, display date, currency, etc.
Here, instead of displaying null, you can display anonymous.

Now create a controller and a view to apply those validations. In this example I am using a default controller and view. The Index action returns a view that contains a form through that a user can fill in the details of the company and submit it.

Sometimes a user needs to implement validation scenarios that are not provided in the MVC framework.

In these kinds of scenarios you need to implement an “IValidatableObject” interface. Using this, you can conduct an in-depth inspection of the model.
In the preceding example, the method used will allow you to access all the properties in the model and you can easily implement the custom validation logic also.

(Important: in the view “ValidationSummary” needs to be true.)
When the user submits the form view, the controller will send a POST request. To respond to this request, we need to create one more ActionResult in our controller.
Considering the view, you may first need to add the model reference as in the following:
Thereafter you add the form inputs and validation that you implemented in the model. It is important that the form inputs should be inside the BeginForm as shown below:







Now your web application will be ready to run. Run the website, if incorrect input values are submitted you will then see invalid input error messages.

This validation only applies to the server side. But there is also a need to do validation from the client side as well. When considering client-side validation, reducing the server load will be a great benefit to the user. The ASP.NET MVC Framework will support client-side validations as well.

To do client-side validation, a few JavaScripts can be used. They are:

1. jQuery
2. jQuery validation library
3. jQuery unobtrusive validation library (developed by Microsoft)

When you open a new ASP.NET.MVC project you will get all the JavaScripts in the scripts folder that you want in the client-side validation. First we should set the configuration inside the <appSettings> tag in the web.config file.



Now we need to add the JavaScript references inside the “BundleConfig.cs” file, creating a new script bundle as shown below.



Then render these scripts in the “_Layout.chtml” file as shown below.

Now you are good to go with client-side validation and server-side validation as well.