C# Bedingung für Erstellen von Objekten

   class Program
    {
        static void Main(string[] args)
        {
            try
            {
                var myObject = new MyObject("rhftjtj");
                Console.WriteLine(myObject.MyString);
                Console.ReadLine();
            }
            catch (Exception exc)
            {
                Console.WriteLine(exc.Message);
                Console.ReadLine();
            }
        }
    }

    public class MyObject
    {
        private string _myString { get; set; }

        public String MyString {
            get {
                return _myString;
            }
        }

        private char[] _notAllowedChars = { 'a', 'b', 'c' };
        public MyObject(string parameterString)
        {
            if (parameterString.ToCharArray().Intersect(_notAllowedChars).Count() > 0)
            {
                throw new ArgumentOutOfRangeException(nameof(parameterString), "Contains not allowed characters");
            }

            _myString = parameterString;
        }
    }