using System;

using System.Linq;

using System.Linq.Expressions;                  

using System.Collections.Generic;

​

public class Program

{

    public static void Main()

    {

        var p = new Person { FirstName = "Bill", LastName= "Gates", MiddleName = string.Empty, Age = 62};

​

        Console.WriteLine(Extensions.GetName(() => p.FirstName));

        Console.WriteLine(Extensions.GetName(() => p.LastName));

        Console.WriteLine(Extensions.GetName(() => p.Age));

        Console.WriteLine(Extensions.GetName(() => p.Birthdate));

        Console.WriteLine(Extensions.GetName(() => p.Parents));

​

        Console.WriteLine(Extensions.GetName(() => p.Age.ToString()));

​

​

        Console.WriteLine(Extensions.EnsureNotNullOrEmpty(() => p.FirstName));

        Console.WriteLine(Extensions.EnsureNotNullOrEmpty(() => p.LastName));

        Console.WriteLine(Extensions.EnsureNotNullOrEmpty(() => p.MiddleName));

    }

​

    // Define other methods and classes here

    public class Person

    {

        public string FirstName { get; set; }

        public string MiddleName { get; set; }

        public string LastName { get; set; }

        public int Age { get; set; }

        public DateTime Birthdate { get; set; }

        public List<Person> Parents { get; set; }

    }

}

​

    public static class Extensions

    {   

        public static string GetName<T>(this Expression<Func<T>> action)

        {

            return GetNameFromMemberExpression(action.Body);

        }

        static string GetNameFromMemberExpression(Expression expression) {

            if (expression is MemberExpression) {

                return (expression as MemberExpression).Member.Name;

            }

            else if (expression is UnaryExpression) {

                return GetNameFromMemberExpression((expression as UnaryExpression).Operand);

            }

            return "MemberNameUnknown";

        }

​

​

        public static bool EnsureNotNullOrEmpty(Expression<Func<string>> member)

        {

            var memberValue = member.Compile()();

            if (string.IsNullOrEmpty(memberValue.ToString()))

            {

                throw new ArgumentException($"This property cannot be null or empty.", member.GetName());

            }

            return true;

        }

    }