using System;

using System.Collections.Generic;

​

public class Program

{

    public static void Main()

    {

        var list = new List<DateTime>();

        list.Add(DateTime.Now.AddMinutes(1));

        list.Add(DateTime.Now.AddMinutes(2));

        list.Add(DateTime.Now.AddMinutes(3));

        list.Add(DateTime.Now.AddMinutes(-1));

        Console.WriteLine("Before:");

        list.ForEach(i => Console.WriteLine(i));

        list.RemoveAll(i => i > DateTime.Now);

        Console.WriteLine("After:");

        list.ForEach(i => Console.WriteLine(i));

    }

}