[导入]WF示例之合同审批

  
       简单合同审批流程

假设一个简单的合同审批流程，对每一个提交的合同，根据合同的不同金额自动发往不同的审批人（部门），审批人可以对合同进行通过或不通过的审批。使用WF设计的流程序如下。

 

第一个节点（CallExtenalMethod）用于将合同信息保存到数据库中。紧接着的IFELSE用于判断合同的金额,以便将合同发往不的审批人。下面的Listen用于等待审事件(通过或不通过)的发生。

业务服务类的设计

<Serializable()> _

Public Class ContractEventArgs

    Inherits ExternalDataEventArgs

 

    Private mOperatorName As String

 

    Public Sub New(ByVal instanceId As Guid, ByVal operatorName As String)

        MyBase.New(instanceId)

        mOperatorName = operatorName

    End Sub

 

    Public ReadOnly Property OperatorName() As String

        Get

            Return mOperatorName

        End Get

    End Property

 

End Class

 

''' <summary>

''' 合同审批服务

''' </summary>

''' <remarks></remarks>

<ExternalDataExchange()> _

Public Interface IContractService

 

    ''' <summary>

    ''' 合同已经通过审批

    ''' </summary>

    Event ContractPassed As EventHandler(Of ContractEventArgs)

 

    ''' <summary>

    ''' 合同没有通过审批

    ''' </summary>

    Event ContractNoPassed As EventHandler(Of ContractEventArgs)

 

    ''' <summary>

    ''' 提交合同审批申请，将合同内容写入数据库

    ''' </summary>

    Function CreateContract(ByVal contractDate As Date, ByVal money As Double, ByVal content As String) As Contract

 

    ''' <summary>

    ''' 通过合同

    ''' </summary>

    Sub PassContract(ByVal id As String)

 

    ''' <summary>

    ''' 拒绝合同

    ''' </summary>

    Sub NoPassContract(ByVal id As String)

End Interface

 

业务服务类的定义要点

接口上必须添加<ExternalDataExchange()>属性，否则不能作为ExternalDataExChangeService中的服务，事件参数必须从ExternalDataEventArgs类继承而来，否则不能被EventDrivenActivity捕获事件。引发事件时必须使用异步方式，代码如下：

    ''' <summary>

    ''' 引发PassContract事件

    ''' </summary>

    Public Sub RaisePassContraCTEvent(ByVal instanceId As Guid)

        ' Raise the event to the workflow

        ThreadPool.QueueUserWorkItem(AddressOf JustCloseTheTicket, _

            New ContractEventArgs(instanceId, "shangfc"))

    End Sub

 

 

    Public Sub JustCloseTheTicket(ByVal o As Object)

        Dim args As ContractEventArgs

        args = CType(o, ContractEventArgs)

 

        RaiseEvent ContractPassed(Nothing, args)

End Sub

 

 

在合同审批表单中应获得对应的WorkflowInstanceID，然后将此调用它的Load方法将它加载到内存中，然后从WorkflowRunTime中获取对应的业务服务(IContractService)，并调用业务服务的方法来引发事件，从而驱动流程向下前进。代码如下：

''' <summary>

    ''' 通过合同的审批

    ''' </summary>

    Protected Sub btnPass_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnPass.Click

        Dim rt As WorkflowRuntime = Application.Get("Workflow")

        Dim inst As WorkflowInstance = rt.GetWorkflow(New Guid(Label1.Text))

        inst.Load()

        Dim es As Workflow.Activities.ExternalDataExchangeService = rt.GetService(GetType(Workflow.Activities.ExternalDataExchangeService))

        Dim cs As ContractWorkFlow.IContractService = es.GetService(GetType(ContractWorkFlow.IContractService))

        cs.PassContract(Label1.Text)

End Sub

文章来源:http://blog.163.com/jhdzkfb22@126/blog/static/4584347520081111127378