Update cell with a value when form field is selected - excel

Question

I have an excel workbook with modeless form. The way it's setup is that: each sheet in the workbook has a tab in the form. Each field in these tabs is Linked to a cell in corresponding sheet. So when a value is changed/updated in the form, it is automatically updated in the relevant cell. The way I am doing this is by using the onChange event for each filed which call's a UDF that does the updating. My question, there are a lot of fields in the form and lots more to be added. Is there a way to update relevant cell when a field in the form is selected without having to add the call to a UDF in onChange event for each field?
I have tried using things like ControlSource but that only one way where it just updates the value in the form but doesn't update the value in the cell when form is updated.
As a side note, unfortunately I cannot share the form or the sheet but am willing to answer any questions
EDIT
Below is the function that updates the field:
Sub UpdateWorksheetValue(ByVal oObj As Object)
Dim oWS As Worksheet
Dim sCurrentValue As String
Dim iC As Long
' Lets check if tag is set
If Len(Trim(oObj.Tag)) = 0 Then
MsgBox "Empty tag found for '" & oObj.Name & "' field. Failed to update field value" & vbCrLf & vbCrLf & "Please contact system administrator with this information", vbCritical + vbOKOnly, "Update Failed"
Exit Sub
ElseIf Len(Trim(Mid(oObj.Tag, InStr(1, oObj.Tag, "¬") + 1))) = 0 Then
MsgBox "Tag for '" & oObj.Name & "' field does not include page title. Failed to update field value" & vbCrLf & vbCrLf & "Please contact system administrator with this information", vbCritical + vbOKOnly, "Update Failed"
Exit Sub
End If
' Set worksheet
Select Case LCase(Trim(Mid(oObj.Tag, InStr(1, oObj.Tag, "¬") + 1)))
Case "client identification"
Set oWS = oWB.Worksheets("Client Identification - Output")
Case "request details"
Set oWS = oWB.Worksheets("Request Details - Output")
Case "db responsible individuals"
Set oWS = oWB.Worksheets("DB Responsible Ind - Output")
Case "additional details"
Set oWS = oWB.Worksheets("Additional Details - Output")
End Select
' Set value
With oWS
' Lets check if tag is set
If Len(Trim(Mid(oObj.Tag, 1, InStr(1, oObj.Tag, "¬") - 1))) = 0 Then
MsgBox "Tag for '" & oObj.Name & "' field does not include corresponding cell information. Failed to update field value in '" & oWS.Name & "' worksheet" & vbCrLf & vbCrLf & "Please contact system administrator with this information", vbCritical + vbOKOnly, "Update Failed"
Exit Sub
End If
' Set the search value
.Range("Z1").Value = Mid(oObj.Tag, 1, InStr(1, oObj.Tag, "¬") - 1)
DoEvents
' If a row with tag text is not found, throw a message and exit sub
If Len(Trim(.Range("Z2").Value)) = 0 Then
MsgBox "Unable to find corresponding cell for '" & oObj.Name & "' field in '" & .Name & "' worksheet. Failed to update field value" & vbCrLf & vbCrLf & "Please ensure that the field's 'Tag' matches a cell in the sheet or contact system administrator", vbCritical + vbOKOnly, "Update Failed"
Exit Sub
End If
' Set field value
Select Case LCase(TypeName(oObj))
Case "textbox", "combobox"
.Range("B" & .Range("Z2").Value).Value = oObj.Value
Case "optionbutton"
If oObj.Value = True Then
.Range("B" & .Range("Z2").Value).Value = oObj.Caption
Else
.Range("B" & .Range("Z2").Value).Value = ""
End If
Case "listbox"
' First lets the current cell value
sCurrentValue = .Range("B" & .Range("Z2").Value).Value
' Now lets build the string for the cell
For iC = 0 To oObj.ListCount - 1
If oObj.Selected(iC) And InStr(1, sCurrentValue, oObj.List(iC)) = 0 Then
sCurrentValue = sCurrentValue & "/" & oObj.List(iC)
ElseIf Not oObj.Selected(iC) And InStr(1, sCurrentValue, oObj.List(iC)) > 0 Then
sCurrentValue = Replace(sCurrentValue, "/" & oObj.List(iC), "")
End If
Next
' And finally, set the value
.Range("B" & .Range("Z2").Value).Value = sCurrentValue
End Select
End With
' Clear object
Set oWS = Nothing
End Sub
EDIT 2
I now have a class called formEventClass as suggested by David. Contents of the class are:
Option Explicit
Public WithEvents tb As MSForms.TextBox
Private Sub tb_Change()
UpdateWorksheetValue (tb)
End Sub
But when I make a change in any given text box, cells are not updated (as per David's suggestion, I've removed the call to UpdateWorksheetValue in text box onChange event. Cells are not updated even when I tab out of the field. As this is working for David, I suspect I am missing something here

Answer 1

If you want to get fancy using WithEvents...
Create a Class Module and name it tbEventClass. Put the following code in this module.
Option Explicit
Public WithEvents tb As MSForms.TextBox
Private Sub tb_Change()
Call UpdateWorksheetValue(tb)
End Sub
This defines a custom class (tbEventClass) which is responsive to the events of it's tb property which is a TextBox. You'll need to map your textboxes to instances of this class during the form's Initialize event:
Public textbox_handler As New Collection
Private Sub UserForm_Initialize()
Dim ctrl As Control, tbEvent As tbEventClass
For Each ctrl In Me.Controls
If TypeName(ctrl) = "TextBox" Then
Set tbEvent = New tbEventClass
Set tbEvent.tb = ctrl
textbox_handler.Add tb
End If
Next
End Sub
Important: You will either need to remove or modify the Change event handlers in the UserForm module to avoid duplicate calls to the "update" procedure. If the only thing going on in those event handlers is the call to your update macro, just get remove the event handlers entirely, they're fully represented by the tbClass. If those events contain other code that does other stuff, just remove or comment out the line(s) that call on your update function.
Update:
This is working for me with the controls within a MultiPage and required ZERO changes to the implemented code above.