using System;

using System.Collections.Generic;

using System.Linq;

using System.Linq.Expressions;

using System.Reflection;

​

public class Program

{

    public static void Main()

    {

        var list = Enumerable.Range(1, 5).Select(i => new Test

        {

        Num = i, Str = i.ToString(), NormalDate = DateTime.Now.AddDays(i), NullableDate = DateTime.Now.AddDays(-i)}).ToList();

        foreach (var item in list)

            Console.WriteLine(item);

        Console.WriteLine();        

        Console.WriteLine("Order by  NullableDate: NUllable<DateTime>");

        foreach (var item in list.OrderBy(Selector<Test, DateTime?>("NullableDate")))

            Console.WriteLine(item);

        Console.WriteLine();        

        Console.WriteLine("Order by descending NormalDate: DateTime");

        foreach (var item in list.OrderByDescending(Selector<Test, DateTime>("NormalDate")))

            Console.WriteLine(item);

        Console.WriteLine();

        Console.WriteLine("Order by descending Num: int");

        foreach (var item in list.OrderByDescending(Selector<Test, int>("Num")))

            Console.WriteLine(item);

        Console.WriteLine();

        Console.WriteLine("Order by descending Str: string");

        foreach (var item in list.OrderByDescending(Selector<Test, string>("Str")))

            Console.WriteLine(item);

    }

​

    public static Func<T, TPropType> Selector<T, TPropType>(string prop)

    {

        var type = typeof (T);

        var param = Expression.Parameter(type);

        return Expression.Lambda<Func<T, TPropType>>(Expression.Property(param, type.GetProperty(prop)), param).Compile();

    }

}

​

public class Test

{

    public int Num

    {

        get;

        set;

    }

​

    public string Str

    {

        get;

        set;

    }

​

    public DateTime NormalDate

    {

        get;

        set;

    }

​

    public DateTime? NullableDate

    {

        get;

        set;

    }

​

    public override string ToString()

    {

        return string.Format("Num: {0} ; Str: {1} ; NormalDate: {2:d} ; NullableDate: {3:d}", Num, Str, NormalDate, NullableDate);

    }

}