如何在CSLA框架中,使用状态机工作流

最近的一个项目里，使用了CSLA框架。CSLA有一个基本的设计原理，就是充分利用数据代理（同时规定BussinessObject is serializable），这个代理保证了csla的5层构架对各种物理部署构架的适应性。从它的框架可以看见，它的数据操作都是在DataPotol中定义，所以我们如果要在csla中使用工作流，切不可违反它的这一规定。

 

DataPortalClient.IDataPortalProxy proxy;

     proxy = GetDataPortalProxy(method.RunLocal);

 

普通的WebApplication的做法是在globel文件里加载工作流，如下所示：

protected void Application_Start(object sender, EventArgs e)

      {

          WorkflowRuntime workflowRuntime = new WorkflowRuntime(ConfigurationParameters.WorkflowName);

          workflowRuntime.AddService(new SqlWorkflowPersistenceService(ConfigurationParameters.WorkflowDBConn));

          workflowRuntime.AddService(new SqlTrackingService(ConfigurationParameters.WorkflowDBConn));

          ExternalDataExchangeService dataService = new ExternalDataExchangeService();

          workflowRuntime.AddService(dataService);

          WorkflowServices service = new WorkflowServices();

          dataService.AddService(service);

          workflowRuntime.StartRuntime();

          Application[ConfigurationParameters.WorkflowName] = workflowRuntime;

      }

在CSLA框架里，我们这样做：建立一个Command对象：

Code  [Serializable]

    public class WorkflowCommand : CommandBase

    {

        private static WorkflowRuntime m_workflowRuntime;

        private static ExternalDataExchangeService m_exchangeService;

        private static bool m_unloadFlag = false;

        public static WorkflowService WorkflowServiceInstance { get; private set; }

        public WorkflowInstance WorkflowInstance { get; private set; }



        public static WorkflowRuntime WorkflowRuntime

        {

            get { return WorkflowCommand.m_workflowRuntime; }

        }



        #region Factory Methods





        public static void InitializeWorkflowRuntime()

        {

            m_unloadFlag = false;

            WorkflowCommand cmd = new WorkflowCommand();

            DataPortal.Execute<WorkflowCommand>(cmd);

        }



        public static void UnloadWorkflowRuntime()

        {

            m_unloadFlag = true;

            WorkflowCommand cmd = new WorkflowCommand();

            DataPortal.Execute<WorkflowCommand>(cmd);

        }



        #endregion



        #region Server-side Code



        protected override void DataPortal_Execute()

        {

            if (!m_unloadFlag)

            {

                m_workflowRuntime = new WorkflowRuntime();

                m_exchangeService = new ExternalDataExchangeService();

                m_workflowRuntime.AddService(new ManualWorkflowSchedulerService());

                m_workflowRuntime.AddService(m_exchangeService);

                m_workflowRuntime.AddService(new SqlWorkflowPersistenceService(ConfigrationParameters.WorkflowConn));

                m_workflowRuntime.AddService(new SqlTrackingService(ConfigrationParameters.WorkflowConn));



                WorkflowServiceInstance = new WorkflowServiceInstance();

                m_exchangeService.AddService(WorkflowServiceInstance);



                m_workflowRuntime.StartRuntime();

            }

            else if (m_workflowRuntime != null)

            {

                m_workflowRuntime.StopRuntime();

            }

        }



        #endregion

然后在globel里加载：

protected void Application_Start(object sender, EventArgs e)

     {

         WorkflowCommand.InitializeWorkflowRuntime();

     }

这样的方式，保证了工作流的初始化在服务端完成，充分体现CSLA的思想。

 

那么如何在Bussiness object里使用这个Command对象呢，我们需要在Bussiness Object的DataPotal里控制工作流的流动和可持续化的操作，比如：

 

Code protected override void DataPortal_Update()

        {

            WorkflowInstance wfInstance = null;

            ManualWorkflowSchedulerService schec = null;

            WorkflowServiceInstance service = null;

            Guid workflowID = Guid.Empty;



            if (isrunWorkflow)

            {

                workflowID = ReadProperty(WorkflowIdProperty);

                wfInstance = WorkflowCommand.WorkflowRuntime.GetWorkflow(workflowID);

                wfInstance.Load();

                schec = WorkflowCommand.WorkflowRuntime.GetService<ManualWorkflowSchedulerService>();

                service = WorkflowCommand.WorkflowRuntime.WorkflowServiceInstance;          

                service.Start(Id, workflowID);

                schec.RunWorkflow(workflowID);

            }



            //TODO:其他数据操作



            wfInstance.Unload();

        }

    }

 

Ok，如上所示，把BussinessObject的数据操作和工作流数据操作都封装进DataPortal方法里，这样保证了工作流可持续化及跟踪服务在服务端运行。

这样，工作流就嵌入到CSLA框架中。

 

在界面，我们需要进入2层的innerException来捕捉工作流的异常：

Codecatch (Exception ex)

{

	if (ex.InnerException.InnerException is System.Workflow.Activities.EventDeliveryFailedException)

	{

		//alert("not allowed!")

		return;

	}

	else	{	}	

}

 

整个过程结束。