‘Make sure that all the wanted references have been set up before doing the imports.
Imports Excel = Microsoft.Office.Interop.Excel ‘To access Excel’s objects.
Imports Office = Microsoft.Office.Core ‘To access Office’s objects.
Imports System.Windows.Forms ‘To access the MessageBox.
Imports Extensibility ‘The IDTExtensibility2 interface.
Imports System.Runtime.InteropServices ‘Defines the GuidAttribute and ProgIdAttribute and to release objects.

<guidattribute (“D5BD9535-51A5-444E-BB23-B83F93C4FB30”), ProgIdAttribute(“NotesTool.Connect”)> _
Public Class Connect

    Implements Extensibility.IDTExtensibility2
    Private Const CONST_TAG As String = “Lotus E-Mail”
    Private Const CONST_PARA_WBOOK As String = “Book”
    Private Const CONST_PARA_WSHEET As String = “Sheet”
    Private Const CONST_PARA_HELP As String = “Help”
    Private Const CONST_PARA_ABOUT As String = “About”
    Private oLotusCommandBar As Office.CommandBar
    Private oBtn As Office.CommandBarButton
    ‘To handle the variable’s click event.
   Private WithEvents cbLotusBtn As Office.CommandBarButton

    Public Sub OnDisconnection(ByVal RemoveMode As Extensibility.ext_DisconnectMode, ByRef custom As System.Array) Implements Extensibility.IDTExtensibility2.OnDisconnection
        Try
            ‘Remove the temporarily custom commandbar.    
           If Not (oLotusCommandBar Is Nothing) Then oLotusCommandBar.Delete()
        Catch ex As Exception
            MessageBox.Show(ex.ToString, g_CONST_TITLE)
        Finally
           ‘Place variables to be handled by the Garbage Collector (GC).    
           oLotusCommandBar = Nothing
            cbLotusBtn = Nothing
            g_xlcell = Nothing
            g_xlRng = Nothing
            g_xlwsSheet = Nothing
            g_xlwbBook = Nothing
            g_xlApp = Nothing
         End Try
    End Sub

    Public Sub OnConnection(ByVal application As Object, ByVal connectMode As Extensibility.ext_ConnectMode, ByVal addInInst As Object, ByRef custom As System.Array) Implements Extensibility.IDTExtensibility2.OnConnection
        Try
            ‘Make sure that the temporarily custom commandbar does not exist.
           If Not (oLotusCommandBar Is Nothing) Then oLotusCommandBar.Delete()
            ‘Cast the main object – declared in a standard module.
           xlApp = CType(application, Excel.Application)
            ‘Create the temporarily commandbar.
           oLotusCommandBar = CType(xlApp.CommandBars.Add(Name:=CONST_TITLE, _
                                                    Position:=Office.MsoBarPosition.msoBarTop, _
                                                    Temporary:=True), Office.CommandBar)
            With oLotusCommandBar
                ‘Add a new button.
               oBtn = CType(.Controls.Add( _
                                            Office.MsoControlType.msoControlButton), _
                                            Office.CommandBarButton)
                ‘Add values to the created new button.
               With oBtn
                    .BeginGroup = True
                    .Caption = “Send Workbooks”
                    .FaceId = 1086
                    .Parameter = CONST_PARA_WBOOK
                    .Style = Office.MsoButtonStyle.msoButtonIconAndCaption
                    .Tag = CONST_TAG
                    .TooltipText = “Send selected workbooks as attachments.”
                End With
                ‘Add an additional new button.
               oBtn = CType(.Controls.Add( _
                                            Office.MsoControlType.msoControlButton), _
                                            Office.CommandBarButton)
                ‘Add values to the created new button.
               With oBtn
                    .BeginGroup = True
                    .Caption = “Send Worksheets”
                    .FaceId = 8
                    .Parameter = CONST_PARA_WSHEET
                    .Style = Office.MsoButtonStyle.msoButtonIconAndCaption
                    .Tag = CONST_TAG
                    .TooltipText = “Send selected worksheets as attachments.”
                End With
                ‘Add an additional new button.
               oBtn = CType(.Controls.Add( _
                                   Office.MsoControlType.msoControlButton), _
                                   Office.CommandBarButton)
                ‘Add values to the created new button.
               With oBtn
                    .BeginGroup = True
                    .FaceId = 984
                    .Caption = “Help”
                    .Parameter = CONST_PARA_HELP
                    .Style = Office.MsoButtonStyle.msoButtonIconAndCaption
                    .Tag = CONST_TAG
                    .TooltipText = “View the help for the tool.”
                End With
                ‘Add an additional new button.
               oBtn = CType(.Controls.Add( _
                                   Office.MsoControlType.msoControlButton), _
                                   Office.CommandBarButton)
                ‘Add values to the created new button.
               With oBtn
                    .BeginGroup = True
                    .FaceId = 611
                    .Caption = “About”
                    .Parameter = CONST_PARA_ABOUT
                    .Style = Office.MsoButtonStyle.msoButtonIconAndCaption
                    .Tag = CONST_TAG
                    .TooltipText = “About the tool.”
                End With
                ‘Make the commandbar visible.
               .Visible = True
            End With
            ‘Set the WithEvents to hook the created buttons, i e all buttons use the same Click event.
           cbLotusBtn = oBtn
        Catch ex As Exception
            MessageBox.Show(ex.ToString, g_CONST_TITLE)
        Finally
            ‘Release object.
           If Not (oBtn Is Nothing) Then oBtn = Nothing
        End Try
    End Sub

    Private Sub cbLotusBtn_Click(ByVal Ctrl As Microsoft.Office.Core.CommandBarButton, ByRef CancelDefault As Boolean) Handles cbLotusBtn.Click
        Try
            ‘Find out which button the user clicked on.
           Select Case Ctrl.Parameter
                Case CONST_PARA_WBOOK
                    Dim frmwbook As New frmwbook
                    ‘By using the method ShowDialog instead of Show makes the
                   ‘form part of the active window.
                   frmwbook.ShowDialog()
                    If Not (frmwbook Is Nothing) Then frmwbook = Nothing
                Case CONST_PARA_WSHEET
                    Dim frmwsheet As New frmwsheet
                    frmwsheet.ShowDialog()
                    If Not (frmwsheet Is Nothing) Then frmwsheet = Nothing
                Case CONST_PARA_HELP
                    Try
                        Show_Help()
                    Catch ex As Exception
                        MessageBox.Show(ex.ToString, g_CONST_TITLE)
                    End Try
                Case CONST_PARA_ABOUT
                    Dim frmabout As New frmAbout
                    frmabout.ShowDialog()
                    If Not (frmabout Is Nothing) Then frmabout = Nothing
            End Select
        Catch ex As Exception
            MessageBox.Show(ex.ToString, g_CONST_TITLE)
        End Try
    End Sub
End Class

            System.Windows.Forms.Application.EnableVisualStyles()
            System.Windows.Forms.Application.DoEvents()