Question : WithEvents using ActiveX controls

I suspect this one to be challenging to answer.  I am trying to trap the update events on an unbound form using WithEvents.  My code has been successful for all but one control type (DateTimePicker ActiveX control).  I need to be able to trap the update event of this control.  Also in my code I have declared and instanciated new class objects for each control type.  This does not seem to me to be an efficient way to do things, but was all I could figure out.  If someone knows of a more efficient way, feel free to post it, otherwise here is my current code.  I have noted the line of failure.

'*********Clas Module Code*****************
Option Compare Database
Option Explicit
'This class is used in conjunction with unbound forms to detect when a user has editied data
Public WithEvents TextBox As TextBox
Public WithEvents ComboBox As ComboBox
Public WithEvents OptionBtn As OptionButton
Public WithEvents CheckBox As CheckBox
Public WithEvents DateTimePic As DTPicker

Private Sub TextBox_AfterUpdate()
  Call TestMessage
End Sub
Private Sub ComboBox_AfterUpdate()
  Call TestMessage
End Sub
Private Sub OptionBtn_AfterUpdate()
  Call TestMessage
End Sub
Private Sub CheckBox_AfterUpdate()
  Call TestMessage
End Sub
Private Sub DateTimePic_Updated()
  Call TestMessage
End Sub
Private Sub TestMessage()
  MsgBox "Test"
End Sub
'*********Clas Module Code Ends*************

'*********Form Code ************
Private TextBox() As New clsTrapUpdates
Private ComboBox() As New clsTrapUpdates
Private OptionBtn() As New clsTrapUpdates
Private CheckBox() As New clsTrapUpdates
Private DateTimePic() As New clsTrapUpdates


Private Sub Form_Load()
  Dim ctl As Control
  Dim txtCount As Long
  Dim cboCount As Long
  Dim optCount As Long
  Dim chkCount As Long
  Dim dtpCount As Long

For Each ctl In Controls
  Select Case ctl.ControlType
    Case acOptionButton
      optCount = optCount + 1
      ReDim Preserve OptionBtn(optCount)
      Set OptionBtn(optCount).OptionBtn = ctl
      ctl.AfterUpdate = "[Event Procedure]"
    Case 119 'This is the numerical constant for ActiveX control DTPicker
      dtpCount = dtpCount + 1
      ReDim Preserve DateTimePic(dtpCount)
      Set DateTimePic(dtpCount).DateTimePic = ctl  <---Runtime Error 13 'Type Mismatch'
      ctl.Update = "[Event Procedure]"
    Case acTextBox
      txtCount = txtCount + 1
      ReDim Preserve TextBox(txtCount)
      Set TextBox(txtCount).TextBox = ctl
      ctl.AfterUpdate = "[Event Procedure]"
    Case acCheckBox
      chkCount = chkCount + 1
      ReDim Preserve CheckBox(chkCount)
      Set CheckBox(chkCount).CheckBox = ctl
      ctl.AfterUpdate = "[Event Procedure]"
    Case acComboBox
      cboCount = cboCount + 1
      ReDim Preserve ComboBox(cboCount)
      Set ComboBox(cboCount).ComboBox = ctl
      ctl.AfterUpdate = "[Event Procedure]"
  End Select
Next ctl
Set ctl = Nothing
End Sub

'*********Form Code Ends*********

Answer : WithEvents using ActiveX controls

Well - you're creating a generic method of hooking in to form controls.  And that's essentially what you'll accomplish.
I personally have never had need to do this - and so wouldn't want to suggest anything different.
I hook into controls and objects events as and when I need them.

I'm a massive fan of maintaining versatility and genericness - but in general I find that a reasonable section of reusable code tapped into and appended as required is enough.
(Sometimes routines made into a large library of classes are very generic and work well - but by the time the code's gone to the bother of instantiating it and setting necessary properties - little, if anything, has been gained.  I'm not saying that's the case here - just that I've never felt the need).

As for its efficiency I wouldn't worry about it too much.
If better solutions exist - they usually present themselves over time.
It's important to have a starting point - don't you find? :-)