C# Online Compiler | .NET Fiddle

using System;
using System.Collections.Generic;

/*****************************************

#ChangingState

    -interface-

    transition
    changeState

    -machine-

    $S0
        |<| handleTransitionExitEvent() ^
        |transition| -> "transition" $S1 ^

    $S1
        |>| handleTransitionEnterEvent() ^
        |changeState| ->> "change state" $S0 ^

    -actions-

    handleTransitionExitEvent
    handleTransitionEnterEvent
##

******************************************/

// ------------------------------------- // 

public class FrameEvent {
	public FrameEvent(string message, Dictionary<string,object> parameters) {
		this._message = message;
		this._parameters = parameters;
	}
	public string _message;
	public Dictionary<string,Object> _parameters;
	public Object _return;
}

public delegate void FrameState(FrameEvent e);

// ------------------------------------- // 

// emitted from framec_v0.3.44
public partial class ChangingState {
    public ChangingState() {
        
        _state_ = _sS0_;
    }
    
    //===================== Interface Block ===================//
    
    public void transition() {
        FrameEvent e = new FrameEvent("transition",null);
        _state_(e);
    }
    
    public void changeState() {
        FrameEvent e = new FrameEvent("changeState",null);
        _state_(e);
    }
    
    
    //===================== Machine Block ===================//
    
    private void _sS0_(FrameEvent e) {
        if (e._message.Equals("<")) {
            handleTransitionExitEvent_do();
            return;
        }
        else if (e._message.Equals("transition")) {
            // transition
            _transition_(_sS1_);
            return;
        }
    }
    
    private void _sS1_(FrameEvent e) {
        if (e._message.Equals(">")) {
            handleTransitionEnterEvent_do();
            return;
        }
        else if (e._message.Equals("changeState")) {
            _changeState_(_sS0_);
            return;
        }
    }
    
    //===================== Actions Block ===================//
    
    protected virtual void handleTransitionExitEvent_do() { throw new NotImplementedException(); }
    protected virtual void handleTransitionEnterEvent_do() { throw new NotImplementedException(); }
    
    
    //=============== Machinery and Mechanisms ==============//
    
    private delegate void FrameState(FrameEvent e);
    private FrameState _state_;
    
    private void _transition_(FrameState newState) {
        FrameEvent exitEvent = new FrameEvent("<",null);
        _state_(exitEvent);
        _state_ = newState;
        FrameEvent enterEvent = new FrameEvent(">",null);
        _state_(enterEvent);
    }
    
    private void _changeState_(FrameState newState) {
        _state_ = newState;
    }
    
}

/********************

public partial class ChangingStateController : ChangingState {

    protected override void handleTransitionExitEvent_do() {}
    protected override void handleTransitionEnterEvent_do() {}
}

********************/


public partial class ChangingStateController : ChangingState {

    protected override void handleTransitionExitEvent_do() {
		Console.WriteLine("Exit $S0");
	}
    protected override void handleTransitionEnterEvent_do() {
		Console.WriteLine("Enter $S1");
	}
}

public class Program
{
	public static void Main()
	{
		var controller = new ChangingStateController();
		controller.transition();
		controller.changeState();	
		controller.transition();
	}
}

    protected virtual void handleTransitionEnterEvent_do() { throw new NotImplementedException(); }
 
using System;
using System.Collections.Generic;
​
/*****************************************
​
#ChangingState
​
    -interface-
​
    transition
    changeState
​
    -machine-
​
    $S0
        |<| handleTransitionExitEvent() ^
        |transition| -> "transition" $S1 ^
​
    $S1
        |>| handleTransitionEnterEvent() ^
        |changeState| ->> "change state" $S0 ^
​
    -actions-
​

Cached Result

Offset: 20
-----
key1 = value 1
key2 = value 2
key3 = value 3
-----
key1 = value 4
key2 = value 5
key3 = value 6