Custom model validator for MvcExtensios

BoolRequired.cs

public class BoolRequired : CustomModelValidator
    {
        private readonly Func<string> _getErrorMsg;

        public BoolRequired(ModelMetadata metadata, ControllerContext controllerContext, Func<string> getErrorMsg)
            : base(metadata, controllerContext)
        {
            _getErrorMsg = getErrorMsg;
        }

        public override IEnumerable<ModelValidationResult> Validate(object value, object model)
        {
            if (!IsValid(value))
            {
                yield return new ModelValidationResult
                {
                    Message = _getErrorMsg()
                };
            }
        }

        private bool IsValid(object value)
        {
            return value != null && (bool)value;
        }

        public override IEnumerable<ModelClientValidationRule> GetClientValidationRules()
        {
            yield return new ModelClientValidationRule { ValidationType = "brequired", ErrorMessage = _getErrorMsg() };
        }
    }

BoolRequiredModelMetadataItemBuilderExtensions.cs

public static class BoolRequiredModelMetadataItemBuilderExtensions
    {
        public static ModelMetadataItemBuilder<bool> BoolRequired(this ModelMetadataItemBuilder<bool> self, string errorMessage)
        {
            return BoolRequired(self, () => errorMessage);
        }

        public static ModelMetadataItemBuilder<bool> BoolRequired(this ModelMetadataItemBuilder<bool> self, Func<string> errorMessage)
        {
            self.ValidateBy((m, c) => new BoolRequired(m, c, errorMessage));
            return self;
        }
    }

brequired.js

(function ($) {
    $.validator.unobtrusive.adapters.addBool("brequired", "required");
})(jQuery)

CustomModelValidator.cs

   public abstract class CustomModelValidator : ModelValidator
    {
        protected CustomModelValidator(ModelMetadata metadata, ControllerContext controllerContext) : base(metadata, controllerContext)
        {
        }

        public sealed override IEnumerable<ModelValidationResult> Validate(object container)
        {
            return Validate(Metadata.Model, container);
        }

        public abstract IEnumerable<ModelValidationResult> Validate(object value, object model);
    }