Public Class Activity1
    Inherits Activity
    Implements IEventActivity, IActivityEventListener(Of QueueEventArgs)

    Public Sub OnEvent(ByVal sender As Object, ByVal e As QueueEventArgs) Implements IActivityEventListener(Of QueueEventArgs).OnEvent
        Dim executionContext As ActivityExecutionContext = CType(sender, ActivityExecutionContext)
        Dim wqs As WorkflowQueuingService = executionContext.GetService(Of WorkflowQueuingService)()
        Dim queue As WorkflowQueue = wqs.GetWorkflowQueue(QueueName)

        Dim item As Object = queue.Dequeue()
        ' ToDo: Implement

        executionContext.CloseActivity()
    End Sub

    Protected Overrides Function Execute(ByVal executionContext As ActivityExecutionContext) As ActivityExecutionStatus
        Dim status As ActivityExecutionStatus
        If IsInEventActivityMode Then
            status = ActivityExecutionStatus.Closed
        Else
            InternalSubscribe(executionContext, Me, False)
            status = ActivityExecutionStatus.Executing
        End If

        Return status
    End Function

    Public ReadOnly Property QueueName() As IComparable Implements IEventActivity.QueueName
        Get
            Return "MyQueueName"
        End Get
    End Property

    Public Sub Subscribe(ByVal parentContext As ActivityExecutionContext, ByVal parentEventHandler As IActivityEventListener(Of QueueEventArgs)) Implements IEventActivity.Subscribe
        InternalSubscribe(parentContext, parentEventHandler, True)
    End Sub

    Public Sub Unsubscribe(ByVal parentContext As ActivityExecutionContext, ByVal parentEventHandler As IActivityEventListener(Of QueueEventArgs)) Implements IEventActivity.Unsubscribe

        ' If we are in the IsInEventActivityMode mode we need to UnregisterForQueueItemAvailable here.
    End Sub

    Private Sub InternalSubscribe(ByVal executionContext As ActivityExecutionContext, ByVal eventHandler As IActivityEventListener(Of QueueEventArgs), ByVal eventActivityMode As Boolean)
        Dim wqs As WorkflowQueuingService = executionContext.GetService(Of WorkflowQueuingService)()
        Dim queue As WorkflowQueue = wqs.CreateWorkflowQueue(QueueName, True)
        queue.RegisterForQueueItemAvailable(eventHandler, QualifiedName)
        IsInEventActivityMode = eventActivityMode
    End Sub

    Public Shared IsInEventActivityModeProperty As DependencyProperty = DependencyProperty.Register("IsInEventActivityMode", GetType(Boolean), GetType(Activity1))

    <Description("This is the description which appears in the Property Browser")> _
    <Category("This is the category which will be displayed in the Property Browser")> _
    <Browsable(True)> _
    <DesignerSerializationVisibility(DesignerSerializationVisibility.Visible)> _
    Public Property IsInEventActivityMode() As Boolean
        Get
            Return (CType((MyBase.GetValue(Activity1.IsInEventActivityModeProperty)), Boolean))
        End Get
        Set(ByVal Value As Boolean)
            MyBase.SetValue(Activity1.IsInEventActivityModeProperty, Value)
        End Set
    End Property
End Class