var name = TypeInfoHelper.GetClassPropertiesName<MyClass,List<string>>(s => myClass.UserName);

var name = TypeInfoHelper.GetClassPropertiesName<MyClass,int>(s => customer.Flag);

TypeInfoHelper.GetPropertyName(s=>myClass.UserName)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Linq.Expressions;
using System.Text;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            var cust = new Customer();
            var addr = new Address(cust);
            string name1 = TypeInfoHelper.GetPropertyName(p => cust.Flag);
            Console.WriteLine(name1);
            string name2 = TypeInfoHelper.GetPropertyName(p => addr.Owner.Remark);
            Console.WriteLine(name2);
            string name3 = TypeInfoHelper.GetPropertyName(p => cust.Orders);
            Console.WriteLine(name3);
            string name4 = TypeInfoHelper.GetPropertyName(p => cust.Orders.FirstOrDefault().Price);
            Console.WriteLine(name4);
            Console.ReadLine();
        }
    }

    public class TypeInfoHelper
    {
        public static string GetPropertyName(Expression<Func<Object, Object>> propery)
        {
            var body = propery.Body.ToString();
            return body.Substring(body.LastIndexOf(".") + 1);
        }

    }

    public class Customer
    {
        public string Name { get; set; }
        public string Remark { get; set; }
        public int Flag { get; set; }

        public List<string> Contacts { get; set; }
        public List<Order> Orders { get; set; }
    }

    public class Order
    {
        public decimal Price { get; set; }
    }

    public class Address
    {
        private Customer customer;

        public string Country { get; set; }
        public string State { get; set; }
        public string Street { get; set; }

        public Customer Owner
        {
            get { return customer; }
        }

        public Address(Customer owner)
        {
            this.customer = owner;
        }
    }

}