Question

I am building a ASP.NET Mvc app. I have a Data model say User

public class user
{
    public int userId {get; private set};
    public string FirstName {get; set;}
}

The validation to be done is that the firstname cannot exceed 50 characters.

I have another presentation model in which i have the property FirstName too. I do not want to repeat the validation logic in both the models. I want to have it in one place and that should be it.

I can do it in a simpler way by adding a function which can be called while setting the property like

private string firstName;
public string FirstName
{
    get
    {
        return firstName;
    }
    set
    {
        if (PropertyValidator.ValidName(value)) // assuming ValidName exists and it will throw an exception if the value is not valid
        {
             firstName = value;
        }
    }
}

But I am looking for something much simpler so that I do not need to add this for every property I need to have it validated. I looked at ValidationAttribute but then again I can validate this only from a controller (ModelState.IsValid). Since this model could be used by some other type of apps like console app, I could not choose that. But if there is a way to use the Mvc's ModelState.IsValid from outside of a controller, that would be awesome. Any suggestions are greatly appreciated.

Thanks!!

Answer 1

You could take a look at FluentValidation. It is a great framework that allows you to separate the validation logic of your model from the model itself, provides easy way to unit test the validation logic and could be used in any type of application and of course seamlessly integrates with ASP.NET MVC.