Actiontest.cs

using System;
using System.Threading.Tasks;

namespace TestOp
{
	class MainClass
	{
		public static void Main (string[] args)
		{
			var foo = new foo();
			foo.Run();
			Console.ReadLine();
		}
	}

	public class foo
	{
		string token;

		public foo ()
		{
			this.token = "Initial Value";
		}

		void DoIt(string someString)
		{
			Console.WriteLine("SomeString is '{0}'", someString);
		}

		public void Run()
		{
			Action op = () => DoIt(this.token);
			this.token = "Changed value";
			op();
		}
	}
}