Public Interface IWorkItem
    'Fixed fields.
    Property BatchVisual As String
    'Optional fields.
    Property DeliverToResource As String
    Property ProductGroup As String
    Property Remark As String
    Property EndTimeStamp As DateTime
    Property Activities As List(Of IActivity)

    ''' <summary>
    ''' Get whether or not all non-read only activities have status finished.
    ''' </summary>
    ''' <returns></returns>
    Function AreAllActivatableActivitiesFinished As boolean
End Interface