VBA - Trapping events on dynamically created Textbox - vba

Question

I am writing a VBA application in Excel. I have a Userform that dynamically builds itself based upon the data contained in one of the worksheets.
All of the code that creates the various comboboxes, textboxes and labels is working.
I created a class module to trap OnChange events for the Comboboxes, and again this works as expected.
Now I have a need to trap OnChange events for some of the textboxes, so I created a new class module modelled on that for the comboboxes to trap the events.
Public WithEvents tbx As MSForms.TextBox
Sub SetTextBox(ctl As MSForms.TextBox)
Set tbx = ctl
End Sub
Public Sub tbx_Change()
Dim LblName As String
MsgBox "You clicked on " & tbx.Name, vbOKOnly
End Sub
The message box is just so that I can confirm it works before I go further.
The problem I'm getting is in the UserForm code module:
Dim TBox As TextBox
Dim tbx As c_TextBoxes
'[...]
Set TBox = lbl
Set tbx = New c_TextBoxes
tbx.SetTextBox lbl
pTextBoxes.Add tbx
This throws up a type mismatch error at Set TBox=lbl. It's the exact same code that works fine for the ComboBox, just with the variables given approriate names. I've stared at this for 2 hours.
Anyone got any ideas? Thanks for any pointers.
Edit - Here's the full userform module that I'm having trouble with:
Private Sub AddLines(FrameName As String, PageName As String)
Dim Counter As Integer, Column As Integer
Dim obj As Object
Dim CBox As ComboBox
Dim cbx As c_ComboBox
Dim TBox As TextBox
Dim tbx As c_TextBoxes
Dim lbl As Control
Set obj = Me.MultiPage1.Pages(PageName).Controls(FrameName)
If pComboBoxes Is Nothing Then Set pComboBoxes = New Collection
If pTextBoxes Is Nothing Then Set pTextBoxes = New Collection
For Counter = LBound(Vehicles) To UBound(Vehicles)
For Column = 1 To 8
Select Case Column
Case 1
Set lbl = obj.Add("Forms.Label.1", "LblMachine" & FrameName & Counter, True)
Case 2
Set lbl = obj.Add("Forms.Label.1", "LblFleetNo" & FrameName & Counter, True)
Case 3
Set lbl = obj.Add("Forms.Label.1", "LblRate" & FrameName & Counter, True)
Case 4
Set lbl = obj.Add("Forms.Label.1", "LblUnit" & FrameName & Counter, True)
Case 5
Set lbl = obj.Add("Forms.ComboBox.1", "CBDriver" & FrameName & Counter, True)
Case 6
Set lbl = obj.Add("Forms.Label.1", "LblDriverRate" & FrameName & Counter, True)
Case 7
Set lbltbx = obj.Add("Forms.TextBox.1", "TBBookHours" & FrameName & Counter, True)
Case 8
Set lbl = obj.Add("Forms.Label.1", "LblCost" & FrameName & Counter, True)
End Select
With lbl
Select Case Column
Case 1
.Left = 1
.Width = 60
.Top = 10 + (Counter) * 20
.Caption = Vehicles(Counter).VType
Case 2
.Left = 65
.Width = 40
.Top = 10 + (Counter) * 20
.Caption = Vehicles(Counter).VFleetNo
Case 3
.Left = 119
.Width = 50
.Top = 10 + (Counter) * 20
.Caption = Vehicles(Counter).VRate
Case 4
.Left = 163
.Width = 30
.Top = 10 + (Counter) * 20
.Caption = Vehicles(Counter).VUnit
Case 5
.Left = 197
.Width = 130
.Top = 10 + (Counter) * 20
Set CBox = lbl 'WORKS OK
Call CBDriver_Fill(Counter, CBox)
Set cbx = New c_ComboBox
cbx.SetCombobox CBox
pComboBoxes.Add cbx
Case 6
.Left = 331
.Width = 30
.Top = 10 + (Counter) * 20
Case 7
.Left = 365
.Width = 30
.Top = 10 + (Counter) * 20
Set TBox = lbl 'Results in Type Mismatch
Set tbx = New c_TextBoxes
tbx.SetTextBox TBox
pTextBoxes.Add tbx
Case 8
.Left = 400
.Width = 30
.Top = 10 + (Counter) * 20
End Select
End With
Next
Next
obj.ScrollHeight = (Counter * 20) + 20
obj.ScrollBars = 2
End Sub
And here's the c_Combobox class module:
Public WithEvents cbx As MSForms.ComboBox
Sub SetCombobox(ctl As MSForms.ComboBox)
Set cbx = ctl
End Sub
Public Sub cbx_Change()
Dim LblName As String
Dim LblDriverRate As Control
Dim i As Integer
'MsgBox "You clicked on " & cbx.Name, vbOKOnly
LblName = "LblDriverRate" & Right(cbx.Name, Len(cbx.Name) - 8)
'MsgBox "This is " & LblName, vbOKOnly
'Set obj = Me.MultiPage1.Pages(PageName).Controls(FrameName)
Set LblDriverRate = UFBookMachines.Controls(LblName)
For i = LBound(Drivers) To UBound(Drivers)
If Drivers(i).Name = cbx.Value Then LblDriverRate.Caption = Drivers(i).Rate
Next
End Sub
And finally, here's the c_TextBoxes class module:
Public WithEvents tbx As MSForms.TextBox
Sub SetTextBox(ctl As MSForms.TextBox)
Set tbx = ctl
End Sub
Public Sub tbx_Change()
Dim LblName As String
'Does nothing useful yet, message box for testing
MsgBox "You clicked on " & tbx.Name, vbOKOnly
End Sub

Answer 1

After some quick testing, I am able to reproduce your error if I declare TBox as TextBox. I do not get an error if I declare TBox as MSForms.TextBox. I would recommend declaring all your TextBox variables with the MSForms qualifier.
Test code is situated similar to yours. I have a MultiPage with a Frame where I am adding a Control.
Private Sub CommandButton1_Click()
Dim obj As Object
Set obj = Me.MultiPage1.Pages(0).Controls("Frame1")
Dim lbl As Control
Set lbl = obj.Add("Forms.TextBox.1", "txt", True)
If TypeOf lbl Is TextBox Then
Debug.Print "textbox found1" 'does not execute
End If
If TypeOf lbl Is MSForms.TextBox Then
Debug.Print "textbox found2"
Dim txt1 As MSForms.TextBox
Set txt1 = lbl 'no error
End If
If TypeOf lbl Is MSForms.TextBox Then
Debug.Print "textbox found3"
Dim txt As TextBox
Set txt = lbl 'throws an error
End If
End Sub
I am not sure why the qualifier is needed for TextBox and not ComboBox. As you can see above, a good test for this is the If TypeOf ... Is ... Then to test which objects are which types. I included the first block to show that lbl is not a "bare" TextBox, but, again, I have no idea why that is. Maybe there is another type of TextBox out there that overrides the default declaration?