gistfile1.cs

        ....

        #region StateMachine

        static ServiceController()
        {
            Define(() =>
                {
                    Initially(
                              When(OnStart)
                                  .Then(sc => sc.Initialize())
                                  .Then(sc => sc.StartAction(sc._instance))
                                  .TransitionTo(Started)
                        );

                    During(Started,
                           When(OnPause)
                               .Then(sc => sc.PauseAction(sc._instance))
                               .TransitionTo(Paused));

                    During(Paused,
                           When(OnContinue)
                               .Then(sc => sc.ContinueAction(sc._instance))
                               .TransitionTo(Started));


                    Anytime(When(OnStop)
                                .Then(sc => sc.StopAction(sc._instance))
                                .TransitionTo(Stopped)
                        );
                });
        }

        public static Event OnStart { get; set; }
        public static Event OnStop { get; set; }
        public static Event OnPause { get; set; }
        public static Event OnContinue { get; set; }

        public static State Initial { get; set; }
        public static State Started { get; set; }
        public static State Stopped { get; set; }
        public static State Paused { get; set; }
        public static State Completed { get; set; }

        #endregion

        .....

This is a code snippet from the TopShelf project. They are using a sister project Mangum to define a state machine to control a logical service instance.

I should add that this was inside a ServiceController class. They seem to create one for each service that is being managed. That Magnum project looks very interesting.