マルチキャストデリゲートでValidation

ValidationByDeletege.cs

using System;

namespace Delegate.History
{
    public class ValidationByDeletege 
    {
        public static Predicate<string> IsNotEmpty()
        {
            return value => value.Trim().Length > 0;
        }
        public static Predicate<string> IsLength(int len)
        {
            return value => value.Length <= len;
        }
        public static Predicate<string> IsNumber()
        {
            return value =>
            {
                int res;
                if (int.TryParse(value, out res)) { return true; }
                return false;
            };
        }

        public static bool Validate<T>(T value, Predicate<T> userCallbacks) 
        {
            foreach (Predicate<T> p in userCallbacks.GetInvocationList()) 
            {
                bool result = p(value);
                if (!result) { return result; }
            }
            return true;
        }

        public static bool User(string value)
        {
            Predicate<string> v1 = IsNotEmpty();
            Predicate<string> v2 = IsLength(10);
            Predicate<string> v3 = IsNumber();
            //マルチキャストデリゲート
            var userCallbacks = v1 + v2 + v3;
            return Validate<string>(value, userCallbacks);
        }
    }
}