工作流加载及本地通信服务常见的异常

1、从Xoml文件加载工作流时runtime.CreateWorkflow(XmlTextReader.Create("workflow.xoml");

异常信息：未处理 System.Workflow.ComponentModel.Compiler.WorkflowValidationFailedException Message="工作流验证失败。"

实质错误为：在未创建新 Activity 类型的情况下直接执行标记时不能使用 "x:Code" / "x:Class"。

处理方式为：删除x:Class/x:Code结点内容；例如下面xoml文件内容的x:Code就无法加载：

<SequentialWorkflowActivity xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/workflow"> <CodeActivity x:Name="codeActivity1" ExecuteCode="SayHello" /> <x:Code><![CDATA[ private int _amount = 500; public int Amount { get { return _amount; } set { _amount = value; } } private void SayHello(object sender, EventArgs e) { Console.WriteLine("Hello, workflow!"); Console.ReadKey(); } ]]></x:Code> </SequentialWorkflowActivity>
2、本地通信服务定义的事件被客户端订阅时需要将触发事件的Sender参数必须设置为null，否则将报错如下：

无法为实例 ID“a7f482a5-dc7d-4700-b17a-7cf6c3dc8ffd”传递接口类型“OrderWorkflowLibrary.IOrderService”上的事件“OrderRequested”。

实质错误为：EventArgs 不可序列化

[ExternalDataExchange]

public interface IOrderService

{

event EventHandler<OrderEventArgs> OrderRequested; //工作流定义中HandleExternalEventActivity活动中指定的外部事件

void NotifyOrderIdled(Guid instanceId, string userId); //工作流定义中CallExternalMethodActivity活动中指定的外部方法

}

[Serializable]

public class OrderService : IOrderService

{

public event EventHandler<OrderEventArgs> OrderRequested;

public void RaiseOrderRequestedEvent(Guid instanceId, string userId)

{

if (OrderRequested != null)

{

OrderEventArgs e = new OrderEventArgs(instanceId, userId);

OrderRequested(this, e); //需要改为：OrderRequested(null, e);

}

}

public event EventHandler<OrderIdledEventArgs> OrderIdled; //被客户代码订阅的事件

public void NotifyOrderIdled(Guid instanceId, string userId)

{

if (OrderIdled != null)

{

OrderIdledEventArgs e = new OrderIdledEventArgs(instanceId, userId);

OrderIdled(this, e); //这里的事件是发布给客户代码而不是工作流故没有问题

}

}

}

客户端调用工作流代码：

private void StartOrderWorkflow()

{

_workflowRuntime = new WorkflowRuntime();

_externalDataExchangeService = new ExternalDataExchangeService();

_workflowRuntime.AddService(_externalDataExchangeService);

_OrderService = new OrderService();

_OrderService.OrderIdled += new EventHandler<OrderIdledEventArgs>(_OrderService_OrderIdled);

_externalDataExchangeService.AddService(_OrderService);

_workflowRuntime.StartRuntime();

_workflowInstance = _workflowRuntime.CreateWorkflow(typeof(OrderWorkflow));

_workflowInstance.Start();

}