天天向上

   1: interface GateState

   2: {

   3:    void enter();

   4:    void payOK();

   5:    void payFailed();

   6: }

   1: class Gate

   2: {

   3:    private GateState state;

   4:    public Gate(GateState _state)

   5:    {

   6:        this.state = _state;

   7:    }

   8:    public Gate()

   9:    {

  10:        state = new CloseGateState(this);

  11:    }

  12:    public void enter()

  13:    {

  14:        this.state.enter();

  15:    }

  16:    public void payOK()

  17:    {

  18:        this.state.payOK();

  19:    }

  20:    public void payFailed()

  21:    {

  22:        this.state.payFailed();

  23:    }

  24:    public void changeState(GateState _state)

  25:    {

  26:        this.state = _state;

  27:    }

  28:  

  29: }

   1: class CloseGateState : GateState

   2: {

   3:    Gate gate;

   4:    public CloseGateState(Gate gate)

   5:    {

   6:        Console.WriteLine("Gate is closed.");

   7:        this.gate = gate;

   8:    }

   9:    public void enter()

  10:    {

  11:        Console.Write("enter: ");

  12:        this.gate.changeState(new CloseGateState(this.gate));

  13:    }

  14:  

  15:  

  16:    public void payFailed()

  17:    {

  18:        Console.Write("payFailed: ");

  19:        this.gate.changeState(new CloseGateState(this.gate));

  20:    }

  21:  

  22:    public void payOK()

  23:    {

  24:        Console.Write("payOK: ");

  25:        this.gate.changeState(new OpenGateState(this.gate));

  26:    }

  27: }

   1: class OpenGateState : GateState

   2: {

   3:     Gate gate;

   4:     public OpenGateState(Gate _gate)

   5:     {

   6:         Console.WriteLine("Gate is open.");

   7:         this.gate = _gate;

   8:     }

   9:     public void enter()

  10:     {

  11:         Console.Write("enter: ");

  12:         this.gate.changeState(new CloseGateState(this.gate));

  13:     }

  14:  

  15:  

  16:     public void payFailed()

  17:     {

  18:         Console.Write("payFailed: ");

  19:         this.gate.changeState(new OpenGateState(this.gate));

  20:     }

  21:  

  22:     public void payOK()

  23:     {

  24:         Console.Write("payOK: ");

  25:         this.gate.changeState(new OpenGateState(this.gate));

  26:     }

  27: }

   1: class Program

   2: {

   3:     static void Main(string[] args)

   4:     {

   5:         Console.WriteLine("case 1.");

   6:         Gate gate = new Gate();

   7:         gate.enter();

   8:         gate.payOK();

   9:         Console.WriteLine("-----------------------");

  10:         Console.WriteLine("case 2.");

  11:         gate.changeState(new CloseGateState(gate));

  12:         gate.enter();

  13:         gate.payFailed();

  14:  

  15:         Console.WriteLine("-----------------------");

  16:         Console.WriteLine("case 3.");

  17:         gate.changeState(new OpenGateState(gate));

  18:         gate.enter();

  19:         gate.payOK();

  20:  

  21:         Console.WriteLine("-----------------------");

  22:         Console.WriteLine("case 4.");

  23:         gate.changeState(new OpenGateState(gate));

  24:         gate.payFailed();

  25:         gate.payOK();

  26:         Console.ReadKey();

  27:     }

  28: }