C# Validation Helper

InvalidModelException.cs

using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.Linq;
using System.Runtime.Serialization;

namespace JimmyBoh.Common.Exceptions
{
    public class InvalidModelException : Exception
    {
        public ValidationResult[] ValidationResults { get; set; }

        public InvalidModelException(IEnumerable<ValidationResult> results)
        {
            ValidationResults = results.ToArray();
        }
        public InvalidModelException(string message) : base(message){ }

        public InvalidModelException(string message, IEnumerable<ValidationResult> results) : base(message, null)
        {
            ValidationResults = results.ToArray();
        }

        // This constructor is needed for serialization.
        protected InvalidModelException(SerializationInfo info, StreamingContext context):base(info,context){}
    }
}

ValidationHelper.cs

using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;

using JimmyBoh.Common.Exceptions;

namespace JimmyBoh.Common.Extensions
{
    public static class ValidationHelper
    {
        /// <summary>
        /// Throws an <seealso cref="JimmyBoh.Common.Exceptions.InvalidModelException">InvalidModelException</seealso> if invalid. 
        /// </summary>
        /// <param name="instance">The object instance to validate.</param>
        public static void Validate(object instance)
        {
            List<ValidationResult> results;
            var isValid = IsValid(instance, out results);

            if(!isValid)
                throw new InvalidModelException(results);
        }

        public static bool IsValid(object instance)
        {
            var vc = new ValidationContext(instance, null, null);

            return Validator.TryValidateObject(instance, vc, null, true);
        }

        public static bool IsValid(object instance, out List<ValidationResult> results)
        {
            var vc = new ValidationContext(instance, null, null);
            results = new List<ValidationResult>();

            return Validator.TryValidateObject(instance, vc, results, true);
        }
    }
}