Public Interface IPluginsApplication//供主程式使用,由主程式实现

    Event Display(ByVal sender As Object, ByVal e As EventArgs)

    Property Caption() As String

    Sub DisplayInput(ByVal Text As String)


End Interface

Public Interface IPlugins//供功能模块使用,由功能模块实现

    Sub Connect(ByVal PluginsApp As IPluginsApplication)

    Sub DIsconnect()

End Interface

Public Property Caption() As String Implements PluginsInterface.IPluginsApplication.Caption
        Get
            Return Me.Text
        End Get
        Set(ByVal value As String)
            Me.Text = value
        End Set
    End Property

    Public Event Display(ByVal sender As Object, ByVal e As System.EventArgs) Implements PluginsInterface.IPluginsApplication.Display
...

 Dim pobj As PluginsInterface.IPlugins

 pobj.Connect(Me)//把主程式开放的接口提供功能模块