Option Compare Database
Option Explicit

Private Const mModuleName   As String = "IViewEvents"

Public Sub OnBeforeDoSomething(ByVal Data As Object, ByRef Cancel As Boolean):  End Sub
Public Sub OnAfterDoSomething(ByVal Data As Object):                            End Sub

Private Sub Class_Initialize()
    Err.Raise 5, mModuleName, AccessError(5) & " - Interface class must not be instantiated."
End Sub

Option Compare Database
Option Explicit

Private Const mModuleName   As String = "IViewCommands"

Public Sub DoSomething(ByVal arg1 As String, ByVal arg2 As Long):   End Sub

Private Sub Class_Initialize()
    Err.Raise 5, mModuleName, AccessError(5) & " - Interface class must not be instantiated."
End Sub

Option Compare Database
Option Explicit

Private Const mModuleName   As String = "ViewAdapter"

Public Event BeforeDoSomething(ByVal Data As Object, ByRef Cancel As Boolean)
Public Event AfterDoSomething(ByVal Data As Object)

Private mView       As IViewCommands

Implements IViewCommands
Implements IViewEvents

Public Function Initialize(View As IViewCommands) As ViewAdapter
    Set mView = mView
    Set Initialize = Me
End Function

Private Sub IViewCommands_DoSomething(ByVal arg1 As String, ByVal arg2 As Long)
    mView.DoSomething arg1, arg2
End Sub

Private Sub IViewEvents_OnBeforeDoSomething(ByVal Data As Object, ByRef Cancel As Boolean)
    RaiseEvent BeforeDoSomething(Data, Cancel)
End Sub
Private Sub IViewEvents_OnAfterDoSomething(ByVal Data As Object)
    RaiseEvent AfterDoSomething(Data)
End Sub

Option Compare Database
Option Explicit

Private Const mModuleName       As String = "ViewAdapter"

Private WithEvents mViewAdapter As ViewAdapter

Private mData As Object

Public Function Initialize(ViewAdapter As ViewAdapter) As Controller
    Set mViewAdapter = ViewAdapter
    Set Initialize = Me
End Function

Private Sub mViewAdapter_AfterDoSomething(ByVal Data As Object)
    ' Do stuff
End Sub

Private Sub mViewAdapter_BeforeDoSomething(ByVal Data As Object, ByRef Cancel As Boolean)
    Cancel = Not Data Is Nothing
End Sub

Option Compare Database
Option Explicit
Option Private Module

Private Const mModuleName   As String = "Constructors"

Public Function NewViewAdapter(View As IViewCommands) As ViewAdapter
    With New ViewAdapter:   Set NewViewAdapter = .Initialize(View):         End With
End Function

Public Function NewController(ByVal ViewAdapter As ViewAdapter) As Controller
    With New Controller:    Set NewController = .Initialize(ViewAdapter):   End With
End Function

Option Compare Database
Option Explicit

Private Const mModuleName   As String = "MyApplication"

Private mController As Controller

Public Function LaunchApp() As Long
    Dim frm As IViewCommands
    ' Open and assign frm here as instance of a Form implementing
    ' IViewCommands and raising events through the callback interface
    ' IViewEvents. It requires an initialization method (or property
    ' setter) that accepts an IViewEvents argument.
    Set mController = NewController(NewViewAdapter(frm))
End Function

Option Explicit
Public Sub DoSomething()
End Sub

Option Explicit
Implements ISomething

Private Sub ISomething_DoSomething()
    'the actual implementation
End Sub

Dim something As ISomething
Set something = New Class1
something.DoSomething

'@Folder StackOverflowDemo
Public Foo As String
Public Event BeforeDoSomething()
Public Event AfterDoSomething()

Public Sub DoSomething()
End Sub

'@Folder StackOverflowDemo
Implements Class1

Private Sub Class1_DoSomething()
    'method implementation
End Sub

Private Property Let Class1_Foo(ByVal RHS As String)
    'field setter implementation
End Property

Private Property Get Class1_Foo() As String
    'field getter implementation
End Property

'@Folder StackOverflowDemo
Implements Class1
Public Event BeforeDoSomething()
Public Event AfterDoSomething()

Private foo As String

Private Sub Class1_DoSomething()
    RaiseEvent BeforeDoSomething
    'do something
    RaiseEvent AfterDoSomething
End Sub

Private Property Let Class1_Foo(ByVal RHS As String)
    foo = RHS
End Property

Private Property Get Class1_Foo() As String
    Class1_Foo = foo
End Property

'@Folder StackOverflowDemo
Option Explicit
Private WithEvents SomeClass2 As Class2 ' Class2 is a "concrete" implementation

Public Sub Test(ByVal implementation As Class1) 'Class1 is the interface
    Set SomeClass2 = implementation ' will not work if the "real type" isn't Class2
    foo.DoSomething ' runs whichever implementation of the Class1 interface was supplied
End Sub

Private Sub SomeClass2_AfterDoSomething()
'handle AfterDoSomething event of Class2 implementation
End Sub

Private Sub SomeClass2_BeforeDoSomething()
'handle BeforeDoSomething event of Class2 implementation
End Sub

Option Explicit

Sub Main()

    Dim oClient As Client
    Set oClient = New Client

    oClient.Run


End Sub

Option Explicit

Implements IEventListener

Private Sub IEventListener_SomethingHappened(ByVal vSomeParam As Variant)
    Debug.Print "IEventListener_SomethingHappened " & vSomeParam
End Sub

Public Sub Run()

    Dim oEventEmitter As EventEmitter
    Set oEventEmitter = New EventEmitter

    oEventEmitter.ServerDoWork Me


End Sub

Option Explicit

Public Sub SomethingHappened(ByVal vSomeParam As Variant)

End Sub

Option Explicit

Public Sub ServerDoWork(ByVal itfCallback As IEventListener)

    Dim lLoop As Long
    For lLoop = 1 To 3
        Application.Wait Now() + CDate("00:00:01")
        itfCallback.SomethingHappened lLoop
    Next

End Sub

[
  uuid(0EA530DD-5B30-4278-BD28-47C4D11619BD),
  hidden,
  custom(0F21F359-AB84-41E8-9A78-36D110E6D2F9, "Microsoft.Office.Interop.Access._FormEvents")

]
dispinterface _FormEvents2 {
    properties:
    methods:
        [id(0x00000813), helpcontext(0x00003541)]
        void Load();
        [id(0x0000080a), helpcontext(0x00003542)]
        void Current();
    '/* omitted lots of other events for brevity */
};

[
  uuid(7398AAFD-6527-48C7-95B7-BEABACD1CA3F),
  helpcontext(0x00003576)
]
coclass Form {
    [default] interface _Form3;
    [source] interface _FormEvents;
    [default, source] dispinterface _FormEvents2;
};

'   clsHUMAN

Public Property Let FirstName(strFirstName As String)
End Property

'   clsEmployee

Implements clsHUMAN

Event evtNameChange()

Private Property Let clsHUMAN_FirstName(RHS As String)
    UpdateHRDatabase
    RaiseEvent evtNameChange
End Property

Private WithEvents Employee As clsEmployee

Private Sub Employee_evtNameChange()
    Me.cmdSave.Enabled = True
End Sub