Question

我最近使用了Stateless状态机。我可以像这样定义转换规则等：

stateMachine.Configure(State.Unknown)
    .Permit(Trigger.StartApplication, State.Initialized)
    .OnEntry(this.DoBeforeTransition)
    .OnExit(this.DoAfterTransition);

stateMachine.Configure(State.Initialized)
    .Permit(Trigger.CheckSomething, State.SomethingChecked)
    .OnEntry(this.DoBeforeTransition)
    .OnExit(this.DoAfterTransition);

然后你就可以触发一个触发器来改变状态。但是，如果要进入特定状态，则需要知道当前状态以及下一个状态。因此，＆＃34;客户＆＃34;如果没有定义直接过渡，状态机需要知识如何达到某种状态。是否有可能称之为＆＃34; goto＆＃34;并且机器会激活所有必需的触发器吗？

Answer 1

你可以这样做只有一个＆＃34; Permit＆＃34;每个州。如果您有多个＆＃34; Permit＆＃34;，那么您无法自动移动工作流程（必须有一些原因可以选择一个Permit / Trigger而不是另一个）。当我说你＆＃34;不能＆＃34;，这在技术上不是，它实际上是。

以下是自动移动工作流程的示例。

using Stateless;
using System;
using System.Runtime.CompilerServices;

namespace MyExample.BAL.WorkFlows
{
    public class TelephoneCallWorkFlow
    {

        private static volatile StateMachine<TelephoneCallStateEnum, TelephoneCallTriggerEnum> SingletonInstance;

        public StateMachine<TelephoneCallStateEnum, TelephoneCallTriggerEnum> Instance
        {
            [MethodImpl(MethodImplOptions.Synchronized)]
            get
            {
                if (SingletonInstance == null)
                {
                    SingletonInstance = new StateMachine<TelephoneCallStateEnum, TelephoneCallTriggerEnum>(TelephoneCallStateEnum.OffHook);

                    SingletonInstance.Configure(TelephoneCallStateEnum.OffHook)
                        .Permit(TelephoneCallTriggerEnum.CallDialed, TelephoneCallStateEnum.Ringing);

                    SingletonInstance.Configure(TelephoneCallStateEnum.Ringing)
                        //removing so there is only one valid path workflow//.Permit(TelephoneCallTriggerEnum.HungUp, TelephoneCallStateEnum.OffHook)
                        .Permit(TelephoneCallTriggerEnum.CallConnected, TelephoneCallStateEnum.Connected);

                    SingletonInstance.Configure(TelephoneCallStateEnum.Connected)
                        //.OnEntry(t => StartCallTimer())
                        //.OnExit(t => StopCallTimer())
                        //removing so there is only one valid path workflow//.Permit(TelephoneCallTriggerEnum.LeftMessage, TelephoneCallStateEnum.OffHook)
                        //removing so there is only one valid path workflow//.Permit(TelephoneCallTriggerEnum.HungUp, TelephoneCallStateEnum.OffHook)
                        .Permit(TelephoneCallTriggerEnum.PlacedOnHold, TelephoneCallStateEnum.OnHold)
                        ;

                    SingletonInstance.Configure(TelephoneCallStateEnum.OnHold)
                        //removing so there is only one valid path workflow//.SubstateOf(TelephoneCallStateEnum.Connected)
                        //removing so there is only one valid path workflow//.Permit(TelephoneCallTriggerEnum.TakenOffHold, TelephoneCallStateEnum.Connected)
                        //removing so there is only one valid path workflow//.Permit(TelephoneCallTriggerEnum.HungUp, TelephoneCallStateEnum.OffHook)
                        .Permit(TelephoneCallTriggerEnum.PhoneHurledAgainstWall, TelephoneCallStateEnum.PhoneDestroyed)
                        ;
                }

                return SingletonInstance;
            }
        }

        public void Fire(TelephoneCallTriggerEnum trigger)
        {
            Console.WriteLine("............[Firing:] {0}", trigger);
            this.Instance.Fire(trigger);
        }
    }
}

public enum TelephoneCallStateEnum
{
    OffHook,
    Ringing,
    Connected,
    OnHold,
    PhoneDestroyed
}

public enum TelephoneCallTriggerEnum
{
    CallDialed,
    HungUp,
    CallConnected,
    LeftMessage,
    PlacedOnHold,
    TakenOffHold,
    PhoneHurledAgainstWall
}

现在＆＃34;自动移动＆＃34;特技。

            TelephoneCallWorkFlow tcwf1 = new TelephoneCallWorkFlow();
            IEnumerable<TelephoneCallTriggerEnum> myPermittedTriggers = tcwf1.Instance.PermittedTriggers;
            while (null != myPermittedTriggers && myPermittedTriggers.Count() > 0)
            {
                if (myPermittedTriggers.Count() > 1)
                {
                    throw new ArgumentOutOfRangeException("You cannot auto-move the workflow when there's more than one trigger");
                }
                TelephoneCallTriggerEnum nextTrigger = myPermittedTriggers.FirstOrDefault();
                Console.WriteLine("About to call the 'next' trigger: --> {0}", nextTrigger);
                tcwf1.Fire(nextTrigger);
                Console.WriteLine("CurrentState: --> {0}", tcwf1.Instance.State);
                myPermittedTriggers = tcwf1.Instance.PermittedTriggers;
            }

你基本上得到PermittedTriggers，并得到第一个（并且为了自动移动工作，每个状态应该只有一个Permitted-Trigger）.....然后调用那个触发器。

同样，实际上（在技术上），如果每个州有一个许可/触发，你只会这样做。这就是为什么我有一个例外，如果有超过1.你可以＆＃34;得到第一个＆＃34;如果超过1，那就没有任何意义。

状态机转换到目标状态并触发转换和状态？

1 个答案: