using System;

using System.Collections.Generic;

using System.ComponentModel.DataAnnotations;

​

public class Program

{

    public static void Main()

    {

        var config1 = new SomeConfiguration

        {

            SomeStringArray = new string[0],

        };

        Console.WriteLine(IsValid(config1, out _));

        var config2 = new SomeConfiguration

        {

            SomeStringArray = null,

        };

        Console.WriteLine(IsValid(config2, out _));

    }

    private static bool IsValid(object validatableObject, out List<ValidationResult> result)

    {

        var validationContext = new ValidationContext(validatableObject);

        var validationResults = new List<ValidationResult>();

​

        if (Validator.TryValidateObject(validatableObject, validationContext, validationResults))

        {

            result = null;

            return true;

        }

​

        result = validationResults;

​

        return false;

    }

​

    private class SomeConfiguration : IValidatableObject

    {

        [Required] // Only checks that the prop is not null, not that it's an empty array.

        // [MinLength(1)] // Doesn't work.

        public string[] SomeStringArray { get; set; }

        public IEnumerable<ValidationResult> Validate(ValidationContext validationContext)

        {

            var results = new List<ValidationResult>();

            // This works:

            if (SomeStringArray.Length < 1)

                results.Add(new ValidationResult("SomeStringArray doesn't contain enough elements."));

            return results;

        }

    }

}

​