using System;

​

namespace StatePatternDemo

{

    using Lab;

    public class Program

    {

        public static void Main()

        {

            var rfq = new Rfq();

            rfq.Method();

            rfq.Method();

            rfq.Method();

            rfq.Method();

        }

    }

}

​

namespace Lab

{

    public interface State

    {

        void Method(Rfq rfq);

    }

​

    public class OpenState : State

    {

        public void Method(Rfq rfq)

        {

            Console.WriteLine("Open");

            rfq.SetState(new CloseState());

        }

    }

​

    public class CloseState : State

    {

        public void Method(Rfq rfq)

        {

            Console.WriteLine("Close");

            rfq.SetState(new CloseState());

        }

    }

​

    public class Rfq

    {

        public State State

        {

            get;

            private set;

        }

​

        public Rfq()

        {

            State = new OpenState();

        }

​

        public void Method()

        {

            State.Method(this);

        }

​

        public void SetState(State state)

        {

            State = state;

        }

    }

}