gistfile1.vb

Imports System.Windows.Forms
Imports Microsoft.Office.Interop.Excel

Public Class ThisAddIn

    Private Sub ThisAddIn_Startup() Handles Me.Startup
        'AddHandler Application.WorkbookOpen, AddressOf Application_WorkbookOpen
        AddHandler Application.WorkbookOpen, wbWorkbookOpenSub2
    End Sub

    Private Sub ThisAddIn_Shutdown() Handles Me.Shutdown

    End Sub

    Private Sub Application_WorkbookOpen(wb As Workbook)
        MessageBox.Show("Opened")
    End Sub

    Private Shared wbWorkbookOpenSub2 As AppEvents_WorkbookOpenEventHandler = Sub(Wb As Microsoft.Office.Interop.Excel.Workbook)
                                                                                  MessageBox.Show("Opened")
                                                                              End Sub
End Class