如需要对事件的绑定，触发有更强的自定义，则可以使用Custom Event来实现

定义

#Region " Events "
    Public Custom Event ThemeChanged As EventHandler
        AddHandler(ByVal value As EventHandler)
            Me.Events.AddHandler("ThemeChangedEvent", value)
        End AddHandler


        RemoveHandler(ByVal value As EventHandler)
            Me.Events.RemoveHandler("ThemeChangedEvent", value)
        End RemoveHandler


        RaiseEvent(ByVal sender As Object, ByVal e As System.EventArgs)
            CType(Me.Events("ThemeChangedEvent"), EventHandler).Invoke(sender, e)
        End RaiseEvent
    End Event
#End Region

触发

 Dim handler As EventHandler = CType(Me.Events("ThemeChangedEvent"), EventHandler)
        If (handler IsNot Nothing) Then
            RaiseEvent ThemeChanged(sender, e)
        End If