完成相关数据服务

完成相关数据服务(correlQteddataservice)

1.在TruckService项目中，你会找到一个名称为

WorkflowTruckTrackingDataService.cs的源文件。你需要打开它准备进行编辑。

2.第一件事是添加该服务执行它的任务时所需要的私有字段。在

WorkflowTruckTrackingDataService类的左大括号的后面添加下面这些代码：

privatestaticWorkflowRuntime_workflowRuntime=null;

privatestaticExternalDataExchangeService_dataExchangeservice=null;

privatestaticTruckServiceDataConnector_dataConnector=null;

privatestaticobject_syncRoot=newobject();

3.在这些私有字段的下面是该服务将触发的事件。这些事件被触发的结果就是工作流实例

将调用一个CollExternolMethod渊］(你可在TruckServiceDotoConnector类中看到它)：

publiceventEventHandler<TruckActivityEventArgs>TruckLeaving;

publiceventEventHandler<TruckActivityEventArgs>Routellpdated;

publiceventEventHandler<TruckActivityEventArgs>TruckArrived;

4.接下来添加两个字段以及对应的属性，你需要它们去对相关的服务实例进行识别：

privateGuidJnstancelD=Guid.Empty;

publicGuidInstancelD

{

get{returnJnstancelD;}

set{JnstancelD=value;}

}

privateInt32_truckID=-1;

publicInt32TruckID

{

get{return_truckID;}

set<_truckID=value;}

}

5.现在我们需要添加两个静态方法：一个是在工作流运行时中注册该服务并对它进行配置,

另一个是去对已经注册的服务实例进行检索：

CreateDataService静态方法和GetRegisteredWorkflowDotoService静态方法

publicstaticWorkflowTruckTrackingDataService

CreateDataService(GuidinstancelD,

WorkflowRuntimeworkflowRuntime,

Int32truckID)

{

lock(_syncRoot)

//Ifwe'rejuststarting,saveacopyoftheworkflow.

//runtimereference

if(_workflowRuntime==null)

_workflowRuntime=workflowRuntime;

}

〃Ifwe'rejuststarting,pluginExternalDataExchangeservice.

if(_dataExchangeservice==null)

<

_dataExchangeService=newExternalDataExchangeService();

_workflowRuntime.AddService(_dataExchangeService);

}

//Checktoseeifwehavealreadyaddedthisdata

//exchangeservice.

TruckServiceDataConnectordataConnector=

(TruckServiceDataConnector)workflowRuntime.GetService(

typeof(TruckServiceDataConnector));

if(dataConnector==null)

_dataConnector=newTruckServiceDataConnector();

_dataExchangeService.AddService(_dataConnector);

}

else

{

_dataConnector=dataConnector;

//Pulltheserviceinstanceweregisteredwiththeconnection

〃object.

returnWorkflowTruckTrackingDataService.

GetRegisteredWorkflowDataService(instanceIDztruckID);

}

}

publicstaticWorkflowTruckTrackingDataService

GetRegisteredWorkflowDataService(GuidinstancelD,

Int32truckID)

{

lock(_syncRoot)

WorkflowTruckTrackingDataServiceworkflowDataService=

TruckServiceDataConnector.GetRegisteredWorkflowDataService(

instancelD,truckID);

if(workflowDataService==null)

workflowDataService=

newWorkflowTruckTrackingDataService(instanceIDztruckID);

TruckServiceDataConnector.RegisterDataService(

workflowDataService);

returnworkflowDataService;

)

}

6.现在添加构造器和析构器：

类的构造器和析构器代码

privateWorkflowTruckTrackingDataService(GuidinstancelD,Int32truckID)

{

this.JnstancelD=instancelD;

this._truckID=truckID;

)

^WorkflowTruckTrackingDataService()

//Cleanup

_workflowRuntime=null;

_dataExchangeService=null;

_dataConnector=null;

}

备注：你可以回忆一下第8章，构造器的作用是防止在服务和连接器类之间出现循环

链接引用。而对于析构器的作用来说，只是实现Disposable并不能完成相应的任务，因为

当从工作流运行时中移除该服务的时候并不调用Dispose方法。

7.在类的构造器的下面，添加下面的读取关联数据的方法:

publicstringRead()

return_dataConnector.RetrieveTruckInfo(InstanceID,TruckID);

}

8.最后添加事件实现的代码:

事件实现的代码

publicvoidRaiseTruckLeavingEvent(Int32truckID,

Int32startingX,

Int32startingY)

if(_workflowRuntime==null)

_workflowRuntime=newWorkflowRuntime();

//Loadspersistedworkflowinstances.

_workflowRuntime.GetWorkflow(JnstanceID);

if(TruckLeaving!=null)

{

TruckLeaving(thisznewTruckActivityEventArgs(_instanceID,

truckID,

startingX,

startingY));

}//if

publicvoidRaiseRouteUpdatedEvent(Int32truckID,

Int32Xz

Int32Y)

if(_workflowRuntime==null)

_workflowRuntime=newWorkflowRuntime();

//Loadspersistedworkflowinstances.

_workflowRuntime.GetWorkflow(_instanceID);

if(RouteUpdated!=null)

Routellpdated(thisznewTruckActivityEventArgs(_instanceID,

truckID,

X,Y));

}//if

}

publicvoidRaiseTruckArrivedEvent(Int32truckID)

if(_workflowRuntime==null)

_workflowRuntime=newWorkflowRuntime();

//Loadspersistedworkflowinstances.

_workflowRuntime.GetWorkflow(_instanceID);

if(TruckArrived!=null)

{

TruckArrived(this,newTruckActivityEventArgs(_instanceID,

truckID));

}//if

)

9.保存该文件并编译该Truckservice项目。如果存在编译错误，请纠正任何出现的编

译错误。

服务类的代码就全部完成了，列表17-3展示了该类的完整代码。TruckSercie本地通

信服务可以准备使用了。我们还没有一个工作流来使用该服务。我们也需要使用可信赖的

wca.exe工具来为我们创建自定义的CQllExternolMethod和HondleExtemolEvent活动。

列表17-3WorkflowTruckTrackingDataService.cs的完整代码

WorkflowTruckTrackingDataService类的完整代码

usingSystem;

usingSystem.Collections.Generic;

usingSystem.Text;

usingSystem.Workflow.Activities;

usingSystem.Workflow.Runtime;

namespaceTruckservice

{

publicclassWorkflowTruckTrackingDataService

privatestaticWorkflowRuntime_workflowRuntime=null;

privatestaticExternalDataExchangeService_dataExchangeservice=null;

privatestaticTruckServiceDataConnector_dataConnector=null;

privatestaticobject_syncRoot=newobject();

publiceventEventHandler<TruckActivityEventArgs>TruckLeaving;

publiceventEventHandler<TruckActivityEventArgs>Routellpdated;

publiceventEventHandler<TruckActivityEventArgs>TruckArrived;

privateGuidJnstancelD=Guid.Empty;

publicGuidInstancelD

{

get{returnJnstancelD;}

set{JnstancelD=value;}

?

privateInt32_truckID=-1;

publicInt32TruckID

get{return_truckID;}

set{_truckID=value;}

}

publicstaticWorkflowTruckTrackingDataServiceCreateDataService(Guid

instancelD,WorkflowRuntimeworkflowRuntime,Int32truckID)

lock(_syncRoot)

〃Ifwe'rejuststarting,saveacopyoftheworkflowruntimereference

if(_workflowRuntime==null)

{

_workflowRuntime=workflowRuntime;

}//if

//Ifwe'rejuststarting,pluginExternalDataExchangeservice

if(_dataExchangeService==null)

_dataExchangeService=newExternalDataExchangeService();

_workflowRuntime.AddService(_dataExchangeService);

}//if

//Checktoseeifwehavealreadyaddedthisdataexchangeservice

TruckServiceDataConnectordataConnector=

(TruckServiceDataConnector)workflowRuntime.GetService(typeof(TruckServiceDataCo

nnector));

if(dataConnector==null)

{

_dataConnector=newTruckServiceDataConnector。；

_dataExchangeService.AddService(_dataConnector);

}//if

else

{

_dataConnector=dataConnector;

}//else

//Pulltheserviceinstanceweregisteredwiththeconnectionobject

return

WorkflowTruckTrackingDataService.GetRegisteredWorkflowDataService(instanceIDz

truckID);

}//lock

}

publicstaticWorkflowTruckTrackingDataService

GetRegisteredWorkflowDataService(GuidinstancelD,Int32truckID)

{

lock(_syncRoot)

WorkflowTruckTrackingDataServiceworkflowDataService=

TruckServiceDataConnector.GetRegisteredWorkflowDataService(instanceIDztruckID);

if(workflowDataService==null)

{

workflowDataService=new

WorkflowTruckTrackingDataService(instanceIDztruckID);

TruckServiceDataConnector.RegisterDataService(workflowDataService);

}//if

returnworkflowDataService;

}//lock

}

privateWorkflowTruckTrackingDataService(GuidinstancelD,Int32truckID)

this.JnstancelD=instancelD;

this._truckID=truckID;

}

~WorkflowTruckTrackingDataService()

<

//Cleanup

_workflowRuntime=null;

_dataExchangeService=null;

_dataConnector=null;

}

publicstringRead()

return_dataConnector.RetrieveTruckInfo(InstanceID,TruckID);

}

publicvoidRaiseTruckLeavingEvent(Int32truckID,Int32startingX,Int32

startingY)

if(_workflowRuntime==null)

_workflowRuntime=newWorkflowRuntime();

_workflowRuntime.GetWorkflow(_instanceID);//loads