C# 实现简单状态机(参考代码)

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:

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();
}
}
}

效果图: