using System;

using System.Collections.Generic;

public class Program

{

    const string Hello = "Hello World";

    public List<string> SomeList { get; set; }

    public static void Main()

    {

        DoSomething("Hello World", x => Console.WriteLine(x));

        DoSomething2(x => Console.WriteLine(x));

        var list = new List<string>

            {

                "Gavno",

                "Sciaky",

                "Sopli"

            };

        var myCollection = new MyCollection(list);

        myCollection.DoSomething(x => Console.WriteLine(x));

    }

    private static void DoSomething(string param,Action<string> doSomething)

    {

        doSomething(param);

    }   

    private static void DoSomething2(Action<string> doSomething)

    {

        doSomething(Hello);

    }   

}

​

public class MyCollection

{

    private List<string> MyList { get; set;}

    public MyCollection(List<string> list)

    {

        MyList = list;

    }

    public void DoSomething(Action<string> doSomething)

    {

        foreach(string elem in MyList)

        {

            doSomething(elem);

        }

    }

}