using System;

using System.Linq;

using System.Reflection;

​

public class Program

{

    public class Class1

    {

        public string A { get; set; }

        public bool B  { get; set; }

        public virtual string C { get; set; }

    }

​

    public class Class2 : Class1 

    {

        public new bool? B { get; set; }

        public override string C {get; set;}

        public int D {get;set;}

    }

    public static void Main()

    {

        var x = typeof(Class2).GetProperties(BindingFlags.Instance | BindingFlags.Public);

        var props = 

            from p in x

            group p by p.Name into g

            select g.OrderByDescending(t => t.DeclaringType == typeof(Class2)).First();

        foreach (var a in props) {

            Console.WriteLine("{0} from {1}", a.Name, a.DeclaringType.Name);

        }

    }

}