Add a custom menu created in .NET to ArcGIS for Desktop
MyBaseMenu.vb
' Copyright 2012 ESRI
' 
' All rights reserved under the copyright laws of the United States
' and applicable international laws, treaties, and conventions.
' 
' You may freely redistribute and use this sample code, with or
' without modification, provided you include the original copyright
' notice and use restrictions.
' 
' See the use restrictions.
' 

Imports ESRI.ArcGIS.ADF.CATIDs
Imports ESRI.ArcGIS.ADF.BaseClasses
Imports System.Runtime.InteropServices

<ComClass(MyBaseMenu.ClassId, MyBaseMenu.InterfaceId, MyBaseMenu.EventsId), _
 ProgId("CustomMenus.MyBaseMenu")> _
Public NotInheritable Class MyBaseMenu
    Inherits BaseMenu
    Implements ESRI.ArcGIS.Framework.IRootLevelMenu

#Region "COM Registration Function(s)"
    <ComRegisterFunction(), ComVisibleAttribute(False)> _
    Public Shared Sub RegisterFunction(ByVal registerType As Type)
        ' Required for ArcGIS Component Category Registrar support
        ArcGISCategoryRegistration(registerType)

        'Add any COM registration code after the ArcGISCategoryRegistration() call

    End Sub

    <ComUnregisterFunction(), ComVisibleAttribute(False)> _
    Public Shared Sub UnregisterFunction(ByVal registerType As Type)
        ' Required for ArcGIS Component Category Registrar support
        ArcGISCategoryUnregistration(registerType)

        'Add any COM unregistration code after the ArcGISCategoryUnregistration() call

    End Sub

#Region "ArcGIS Component Category Registrar generated code"
    ''' <summary>
    ''' Required method for ArcGIS Component Category registration -
    ''' Do not modify the contents of this method with the code editor.
    ''' </summary>
    Private Shared Sub ArcGISCategoryRegistration(ByVal registerType As Type)
        Dim regKey As String = String.Format("HKEY_CLASSES_ROOT\CLSID\{{{0}}}", registerType.GUID)
        MxCommandBars.Register(regKey)

    End Sub
    ''' <summary>
    ''' Required method for ArcGIS Component Category unregistration -
    ''' Do not modify the contents of this method with the code editor.
    ''' </summary>
    Private Shared Sub ArcGISCategoryUnregistration(ByVal registerType As Type)
        Dim regKey As String = String.Format("HKEY_CLASSES_ROOT\CLSID\{{{0}}}", registerType.GUID)
        MxCommandBars.Unregister(regKey)

    End Sub

#End Region
#End Region

#Region "COM GUIDs"
    ' These  GUIDs provide the COM identity for this class 
    ' and its COM interfaces. If you change them, existing 
    ' clients will no longer be able to access the class.
    Public Const ClassId As String = "adb44f5a-b2e4-4c72-a2d4-b46a2c190f6e"
    Public Const InterfaceId As String = "d3088ef5-0b44-49c9-809a-8234f178d79c"
    Public Const EventsId As String = "039e2773-1135-425e-90d6-f13e3208c9bb"
#End Region

    ' A creatable COM class must have a Public Sub New() 
    ' with no parameters, otherwise, the class will not be 
    ' registered in the COM registry and cannot be created 
    ' via CreateObject.
    Public Sub New()
        '
        'TODO: Define your menu here by adding items
        '
        AddItem("esriArcMapUI.ZoomInFixedCommand")
        BeginGroup() 'Separator
        AddItem("{FBF8C3FB-0480-11D2-8D21-080009EE4E51}", 1) 'undo command
        AddItem(New Guid("FBF8C3FB-0480-11D2-8D21-080009EE4E51"), 2) 'redo command

        BeginGroup() ' Add a separator.
        AddItem("CustomMenus.AddShapefile", 3) ' Add custom functionality and add shapefile as a submenu.

    End Sub

    Public Overrides ReadOnly Property Caption() As String
        Get
      Return "My_Menu"
    End Get
    End Property

    Public Overrides ReadOnly Property Name() As String
        Get
      Return "MyBaseMenu"
    End Get
    End Property
End Class