using System;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        var list = new List<int> { 1, 2, 3 };

​

        foreach(var a in list)

        {

            if (a == 2) {

                list.RemoveAll(x => x == 2);

                break;

            }

        }

        list.ForEach(i => Console.Write("{0}\t", i));

    }

}