C# 实现简单状态机

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using System;
namespace StateMachine2.State {
    public enum AnimationState {
        Walk = 1,
        Dead,
    }

    public abstract class State {
        abstract public int GetStateId{ get; }
        abstract public void Enter(StateEvent data);
        abstract public void Execute(StateEvent data);
        abstract public void Exit(StateEvent data);
    }

    //状态运行时候的参数
    public class StateEvent {
        public string data;
    }

    //行走状态
    public class State_Walk : State {
        public const int ID = 1;

        public override int GetStateId {
            get {
                return ID;
            }
        }

        public override void Enter(StateEvent data) {
            Console.WriteLine("角色行走-进入");
        }

        public override void Execute(StateEvent data) {
            Console.WriteLine("角色行走-执行中");
        }

        public override void Exit(StateEvent data) {
            Console.WriteLine("角色行走-退出");
        }
    }

    //死亡状态
    public class State_Dead : State {
        public const int ID = 2;
        public override int GetStateId {
            get {
                return ID;
            }
        }

        public override void Enter(StateEvent data) {
            Console.WriteLine("角色死亡-进入");
        }

        public override void Execute(StateEvent data) {
            Console.WriteLine("角色死亡-执行中");
        }

        public override void Exit(StateEvent data) {
            Console.WriteLine("角色死亡-退出");
        }
    }

    public class StateMachine {
        private State currentState = null;
        private State previousState = null;
        private StateEvent dataEvent = null;
        private bool isStop;

        public State CurrentState {
            get {
                return currentState;
            }
        }

        public State PreviousState {
            get {
                return previousState;
            }
        }

        public bool IsStop {
            get {
                return isStop;
            }

            set {
                isStop = value;
            }
        }

        private State GetState(AnimationState animationState) {
            switch (animationState) {
                case AnimationState.Walk: return new State_Walk();
                case AnimationState.Dead: return new State_Dead();
            }
            return new State_Walk();
        }

        public void ChangeState(AnimationState animationState, StateEvent data,StateEvent previousData = null) {
            ChangeState(GetState(animationState),data, previousData);
        }

        public void ChangeState(State state,StateEvent data, StateEvent previousData = null) {
            //如果切换的状态就是本状态,就退出
            if (currentState != null && state.GetStateId == currentState.GetStateId)
                return;

            //退出上一个状态
            if (previousState != null)
                previousState.Exit(previousData);

            //设置进状态,进入新状态
            currentState = state;
            dataEvent = data;
            currentState.Enter(data);
        }

        public void Update() {
            if (currentState == null) {
                Console.WriteLine("当前没有状态可以执行");
                return;
            } else if (IsStop) {
                Console.WriteLine("状态机已经停止");
                return;
            } else {
                currentState.Execute(dataEvent);
            }
        }
    }
}

执行代码:

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using StateMachine2.State;
using System;

namespace StateMachine2 {
    class Program {
        static void Main(string[] args) {
            StateMachine sm = new StateMachine();
            sm.ChangeState(AnimationState.Walk, new StateEvent() { data = "行走需要的参数" });
            sm.Update();       //执行行走状态 
            sm.Update();       //执行行走状态     
            
            sm.ChangeState(AnimationState.Dead, new StateEvent() { data = "死亡需要的参数" });
            sm.Update();
            sm.IsStop = true;   //停止状态机

            sm.Update();        //再次执行状态

            Console.WriteLine("结束程序");
            Console.ReadLine();
        }
    }
}

本文来自：https://www.cnblogs.com/plateFace/p/5018686.html