fluent validation still showing errors from [Required] data annotation

Question

Summary of question: is it possible to clear the list of errors from the model state when a fluent validator is resolved for a particular model? That way fluent validation overrides the default behaviour in the data annotation model provider, rather than compliments it?

I am using fluent validation like this:

FluentValidationModelValidatorProvider.Configure(
    _ =>
        {
            // This does not seem to work, or i am misunderstanding it?
            _.AddImplicitRequiredValidator = false;
        });

I use autofac for a container, but fluent validation is not actually using the container yet. I have it configured as above.

I have a model like this:

[Validator(typeof(PartyModelValidator))]
public class PartyModel
{

The validator validates like this...

public class PartyModelValidator : AbstractValidator<PartyModel>
{
    /// <summary>
    /// Initialises a new instance of the <see cref="PartyModelValidator"/> class.
    /// </summary>
    public PartyModelValidator()
    {
        this.RuleFor(_ => _.Client)
            .SetValidator(new ClientValidator())
            .When(_ => _.SelectedPartyTab == PartyType.Person);
        this.RuleFor(_ => _.Organisation)
            .SetValidator(new OrganisationValidator())
            .When(_ => _.SelectedPartyTab == PartyType.Organisation);

The validation is working as it should, except that there are [Required] attributes on some of the person and organisation objects.

These [Required] attributes are appearing as validation errors. I get these errors even when the entire object is actually null.

How do I get fluent validation to ignore data annotation properties when a specific fluent validator is configured as above? I would prefer to leave the annotations on the objects, as they serve other purposes besides just view validation?

Answer 1

This does the trick, in case anyone else needs the code, here it is.

/// <summary>
/// The fluent validation model validator provider ex.
/// </summary>
internal class FluentValidationModelValidatorProviderEx : FluentValidationModelValidatorProvider
{
    /// <summary>
    /// Initialises a new instance of the <see cref="FluentValidationModelValidatorProviderEx"/> class.
    /// </summary>
    /// <param name="validatorFactory">
    /// The validator factory.
    /// </param>
    public FluentValidationModelValidatorProviderEx(IValidatorFactory validatorFactory) : base(validatorFactory)
    {
    }

    /// <summary>
    /// get the fluent validators.
    /// </summary>
    /// <param name="metadata">The metadata.</param>
    /// <param name="context">The context.</param>
    /// <returns>the set of validators, if any validators are resolved.</returns>
    /// <remarks>If the fluent validator(s) are supplied, then clear the current set of model errors.</remarks>
    public override IEnumerable<ModelValidator> GetValidators(ModelMetadata metadata, ControllerContext context)
    {
        var validators = base.GetValidators(metadata, context);
        var modelValidators = validators as ModelValidator[] ?? validators.ToArray();
        if (modelValidators.Any())
            context.Controller.ViewData.ModelState.Clear();
        return modelValidators;
    }

    /// <summary>
    /// configure fluent validation.
    /// </summary>
    /// <param name="configurationExpression">The configuration expression.</param>
    internal static void ConfigureFluentValidation(Action<FluentValidationModelValidatorProvider> configurationExpression = null)
    {
        configurationExpression = configurationExpression ?? (Action<FluentValidationModelValidatorProvider>)(param0 => { });
        FluentValidationModelValidatorProvider validatorProvider = new FluentValidationModelValidatorProviderEx((IValidatorFactory)null);
        configurationExpression(validatorProvider);
        DataAnnotationsModelValidatorProvider.AddImplicitRequiredAttributeForValueTypes = false;
        ModelValidatorProviders.Providers.Add((ModelValidatorProvider)validatorProvider);
    }
}