Disable Model Validation in Asp.Net MVC

问题:

How do I disable Model validation for a single Action in a Controller ? Or can I do it per model by registering the model type at startup somewhere ?

I want the ModelBinder to bind to the model, but afterwards it should not perform the model validation.

The reason why i dont want validation to happen is because i am trying to move the logic from the controllers to a service layer which will be responsible for validating the models as i cant assume that models being passed to a service contains valid data.

As I understand this is the recommend approach (to not have logic in the controllers), so I find it a bit strange that i cant seem to find anything about how the model validation can be disabled (per action or per model type).

Please notice that I dont want to disable model validation for the entire webapplication (by removing the validation providers), and i dont want to disable the input validation that checks for malicious code being posted.

---

UPDATE

I am using .Net 4.0 and MVC 3 Preview 1

回答1:

Just remove the items you don´t need before checking if the model is valid

ModelState.Remove("Email");
if (ModelState.IsValid)
{
   // your logic
}

回答2:

I've solved this problem with this code:

public ActionResult Totals(MyModel model)
{
    ModelState.Clear();
    return View(model);
}

Not sure it's the right way though.

回答3:

Unfortunately there seems to be no easy way to disable the model validation happening in the ModelBinder except for registering every single model type you don’t want to validate (including nested complex types) with a specific ModelBinder. It can be done with the following code:

ModelBinders.Binders[typeof(MyModelType)] = new NonValidatingModelBinder();

Creating a SkipValidationAttribute that can be attached to action methods or action method parameters doesn’t seem possible as it should be implemented in the ControllerActionInvoker, but there is no way of letting the ModelBinder know that it should do any validation in the SetProperty() and OnModelUpdated methods when calling BindModel() in the GetParameterValue() method.

回答4:

I would recommend you perform validation in both places rather than trying to turn off validation in the UI. I understand your point that the service cannot assume that it's being passed valid data - that is a valid concern and is the reason your service should have validation. But you should also have validation in your UI. This is also nice because you can have client-side validation to prevent user errors and give you users a better experience.

回答5:

I definitely dislike this addition in the 2.0 version, because, as you stated in your question, validation makes more sense in the Service layer. In this way you can reuse it in other non-web applications, and test it more easily without having to mock the auto-validation mechanism.

Validation in Controller layer is pointless because in this part you can only verify model data and not business rules. For example, think of a service responsible of adding new comments and a user that wants to post a new one, the data in the comment he/she is posting may be valid, but what happens if the user is banned to comment because of misbehavior in the past? You should do some validation in the Service layer to ensure this is not happening, and if it does, throwing an exception. In short, validation must be done in the Service layer.

I use xVal as my Validation framework because it's compatible with the DataAnnotationModel, allows me to place validation wherever I want and performs client-side validation without extra-effort, even remote-client side. This is how I use it at the beginning of each of my services, for example, a login service:

public void SignIn(Login login) {
    var loginErrors = DataAnnotationsValidationRunner.GetErrors(login);

    // Model validation: Empty fields?
    if (loginErrors.Any())
        throw new RulesException(loginErrors);

    // Business validation: Does the user exist? Is the password correct?
    var user = this._userRepository.GetUserByEmail(login.Email);

    if (user == null || user.Password != login.Password)

        throw new RulesException(null, "Username or password invalids");

    // Other login stuff...
}

Simple, web-independent and easy... then, in the Controller:

public RedirectResult Login(Login login) {

    // Login the user

    try {

        this._authenticationRepository.SignIn(login);

    } catch (RulesException e) {

        e.AddModelStateErrors(base.ModelState, "Login");

    }

    // Redirect

    if (base.ModelState.IsValid)
        return base.Redirect(base.Url.Action("Home"));
    else return base.Redirect(base.Url.Action("Login"));
}

回答6:

I know that this already been answered but what you really needed was to extend the DataAnnotationsValidatorProvider and override the GetValidators method.

Then, on startup, you would remove the DataAnnotationsValidatorProvider from ModelValidatorProviders.Providers and add your new one.

Needless to say, if you simply don't want any validation at all, you can simply have the GetValidators method returning an empty collection.

In my case, I need to remove validation only when submitting the forms while still keeping the client-side validation, hence the following:

public class DynamicModelValidatorProvider : DataAnnotationsModelValidatorProvider
{
   GetValidators(ModelMetadata metadata, ControllerContext context, IEnumerable<Attribute> attributes)
    {
        if (context.HttpContext.Request.HttpMethod == "POST")
        {
            return new ModelValidator[] { };
        }

        return base.GetValidators(metadata, context, attributes);
    }
}

回答7:

I use [ ValidateInput( false )]

Not sure if this prevents model validation, or only IIS submit validation.