using System;

using System.Linq;

public class Program

{

    public class User

    {

        public int Id { get; set; }

        public string Name { get; set; }

    }

​

    public static void Main()

    {

        string[] propertyNames = typeof(User).GetProperties().Select(p => p.Name).ToArray();

        Console.WriteLine(string.Join(",", propertyNames));

    }

}