Data validation list is being ignored - excel

Question

I have the following situation: on one cell, I have a Data - validation - list which should restrict the user to selecting only items from that list.
On the same cell I have on change triggers in VBA, so when the cell value is changed it also records the change into a Changelog sheet (it uses undo to get the previous value, and undo again to redo the change to the new value)
The problem is, right now, the Data - validation - list is being totally ignored, so the users can put what ever they want in that specific cell, even though I have "Show error" checked.
Is there a way to enforce the list validation, so the users can only select items from the list and not enter whatever they want? Or to trigger the on cell change event after the validation?
Maybe someone can clarify the order in which these things happen.

Answer 1

I recently worked on range.Validation.type=xlValidateList and wanted to prevent paste and cut and disallow typing wrong characters into the cell containing the dropdown list(and making it possible to type characters that match an entry in the list and show that entry).
While working on the last thing that was not OK (cutting a dropdown and pasting it into another cell already containing a dropdown) I discoverd an EASY way of prohibiting paste and cut for Data Validation Lists that do allow further processing depending on what has been entered,
the following code has to be on the worksheet module.
It prevents the user from destroying Data Validation on cells and because of that using Application.Undo to revert to the state before pasting or cutting is no longer needed.
I don't know if it makes a difference but I protected the sheet and unlocked the cells the user may alter.
Private Function HasValidation(ByVal rng As Range) As Boolean
' See: https://superuser.com/questions/870926/restrict-paste-into-dropdown-cells-in-excel
' Returns True if every cell in Range r uses Data Validation
On Error Resume Next
Dim rngType: rngType = rng.Validation.Type
HasValidation = (Err.number = 0)
End Function
Private Sub Worksheet_SelectionChange(ByVal Target As Range)
' Switch DragAndDrop on/off on a range containing DataValidation
Dim modeCutCopy: modeCutCopy = Application.CutCopyMode
Dim usesValidation: usesValidation = HasValidation(Target)
If ((usesValidation = True) And (modeCutCopy <> 0)) Then Application.CutCopyMode = False ' MUST reset to avoid copying / cutting xlValidateList into another xlValidateList
' Turn DragAnddDrop on/off depending on if a cell uses Validation or not
If (usesValidation = Application.CellDragAndDrop) Then Application.CellDragAndDrop = (Not usesValidation)
GoTo SKIP
' Don't allow DragAndDrop if Target intersects with specified ranges
Dim myRange As Range
Set myRange = Worksheets("Evenementen").Range("Oordeel", "Waardering")
Dim rngIntersect As Range
Set rngIntersect = Application.Intersect(Target, myRange)
Application.CellDragAndDrop = (rngIntersect Is Nothing)
'' CheckInputValidationList(Target) ' Sophisticated testing and actions depending on the selection made
'' CheckInputValidationList(Target, myRange) ' Sophisticated testing and actions depending on the selection made for specific ranges
SKIP:
Debug.Print "SelectionChange " & Target.Address & " usesValidation=" & usesValidation & " cellDragAndDrop=" & Application.CellDragAndDrop
End Sub
In this case there are two named ranges containing (different) Data Validation Lists.
As soon as the user clicks on a cell a check will be performed if that cell uses data validation.
If so cut and paste will be turned off and CutCopyMode will be cleared until the user selects another cell.
Important is to retrieve the current CutCopyMode BEFORE any VBA-code will be executed that changes something as VBA will automatically change CutCopyMode from xlCut or xlCopy into 0 when something changes.
That initiall state is required to avoid pasting a dropdownlist over another.
The Worksheet_SelectionChange subroutine contains SKIPPED code that does something similar if a user accesses a cell in one of two ranges.
It also contains the (turned into comment) code to perform additional actions when the user selects a cell. That code might also be put in worksheet_Change