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用StatePattern来实现一个简单的状态机

发布时间:2022-07-27 13:55:18

首先要理解 State Pattern 模式。

http://www.dofactory.com/net/state-design-pattern

Definition

Allow an object to alter its behavior when its internal state changes. The object will appear to change its class.  


UML class diagram




Participants

    The classes and objects participating in this pattern are:

    • Context  (Account)
      • defines the interface of interest to clients
      • maintains an instance of a ConcreteState subclass that defines the current state.
    • State  (State)
      • defines an interface for encapsulating the behavior associated with a particular state of the Context.
    • Concrete State  (RedState, SilverState, GoldState)
      • each subclass implements a behavior associated with a state of Context

先画个状态机用来接收和处理数据。

开始定义Base状态和各个状态

    public abstract class StateBase
    {
        public abstract void Enter(Monitor context);

        public virtual void Exit(Monitor context)
        {
            Console.WriteLine("Exiting current state: {0}", context.CurrentState.StateName); 
        }

        public string StateName
        {
            get;
            set;
        }
    }
    public class ConnectState : StateBase
    {
        public ConnectState()
        {
            this.StateName = "Connect"; 
        }
        public override void Enter(Monitor context)
        {
            Console.WriteLine("Enter - {0}", context.CurrentState.StateName);
            context.MoveToNextState(new ReceiveDataState()); 
        }
    }

Create a context class, and set initial state to start running.

   public class Monitor
    {
        public Monitor()
        {
        }

        public void MoveToNextState(StateBase nextState)
        {
            Console.WriteLine("Changing state...");
            this.CurrentState.Exit(this);
            this.CurrentState = nextState;
            this.CurrentState.Enter(this); 
        }

        public void Start()
        {
            this.CurrentState = new NotStartState();
            this.CurrentState.Enter(this); 
        }

        public StateBase CurrentState
        {
            get;
            set;
        }

开始使用状态机

        static void Main(string[] args)
        {
            Monitor m = new Monitor();
            m.Start(); 
        }

/template/Home/DawnNew/PC/Static

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