ASP.NET The model in MVC3 is self-validating, which is via the System.ComponentModel.DataAnnotations namespace from NET4. All we need to do is add the corresponding Attributes to the attributes of the Model class, and then the MVC3 framework will do the validation for us. I will use the login that comes with the MVC3 project template as an example to explain the validation of the model. 1. Enable Client Validation Client-side validation is mainly to improve the user experience, and the validation is completed without the web page being brushed back. The first step is to enable client validation in web.config, which is already available in the template project that comes with MVC3