Auto-Updated Validated Cell When Source Value Changes - excel

Question

I'm trying to update cells that have data validation restrictions on them automatically.
For example - Sheet1 has below column (Column E):
Package Identifier
A
B
C
where the values are taken from the same named column (Column D) in Sheet2.
The below code works for MANUAL changes only
Sheet2 Code:
Private Sub Worksheet_Change(ByVal Target As Range)
Application.ScreenUpdating = False
Dim count_cells As Integer
Dim new_value As String
Dim old_value As String
Dim rng As Range
For count_cells = 1 To Range("D1").CurrentRegion.Rows.Count - 1
Set rng = Worksheets("Sheet1").Range("E3:E86")
If Intersect(Target, Range("D" & count_cells + 1)) Is Nothing Then
Else
Application.EnableEvents = False
new_value = Target.Value
Application.Undo
old_value = Target.Value
Target.Value = new_value
rng.Replace What:=old_value, Replacement:=new_value, LookAt:=xlWhole
Target.Select
End If
Next count_cells
Application.EnableEvents = True
Application.ScreenUpdating = True
End Sub
So, if i manually change value B to Z, all the corresponding values that were B on Sheet1 now change to Z. The problem is, Package Identifier on Sheet2 is dictated by concatenating other columns
=CONCATENATE(B35, "-", "Package", "-", TEXT(C35, "#000"))
This piece of code breaks when trying to use it with the above formula. How can i make this set of code trigger on this formula based output?

Answer 1

Assuming this is how the Validation sheet looks
and this is how the Source sheet looks
Let's say user selects first option in Validation sheet.
Now go back to Source sheet and change 1 to 2 in cell C2.
Notice what happens in Validation sheet
If this is what you are trying then based on the file that you gave, test this code.
Option Explicit
Private Sub Worksheet_Change(ByVal Target As Range)
Dim aCell As Range
Dim NewSearchValue As String
Dim OldSearchValue As String
Dim NewArrayBC As Variant
Dim OldArrayA As Variant, NewArrayA As Variant
Dim lRow As Long, PrevRow As Long
On Error GoTo Whoa
Application.EnableEvents = False
If Not Intersect(Target, Range("B:C")) Is Nothing Then
lRow = Range("A" & Rows.Count).End(xlUp).Row
'~~> Store new values from Col A, B and C in an array
NewArrayBC = Range("B1:C" & lRow).Value2
NewArrayA = Range("A1:A" & lRow).Value2
Application.Undo
'~~> Get the old values from Col A
OldArrayA = Range("A1:A" & lRow).Value2
'~~> Paste the new values in Col B/C
Range("B1").Resize(UBound(NewArrayBC), 2).Value = NewArrayBC
'~~> Loop through the cells
For Each aCell In Target.Cells
'~~> Check if the prev change didn't happen in same row
If PrevRow <> aCell.Row Then
PrevRow = aCell.Row
NewSearchValue = NewArrayA(aCell.Row, 1)
OldSearchValue = OldArrayA(aCell.Row, 1)
Worksheets("Validation").Columns(2).Replace What:=OldSearchValue, _
Replacement:=NewSearchValue, Lookat:=xlWhole
End If
Next aCell
End If
Letscontinue:
Application.EnableEvents = True
Exit Sub
Whoa:
MsgBox Err.Description
Resume Letscontinue
End Sub

Answer 2

A different approach from Sid's...
Instead of updating values in the DV cells when the source range changes, this replaces the selected value with a link to the matching cell in the DV source range.
Private Sub Worksheet_Change(ByVal Target As Range)
Dim rngV As Range, rng As Range, c As Range, rngList As Range
Dim f As Range
On Error Resume Next
'any validation on this sheet?
Set rngV = Me.Cells.SpecialCells(xlCellTypeAllValidation)
On Error GoTo 0
If rngV Is Nothing Then Exit Sub 'no DV cells...
Set rng = Application.Intersect(rngV, Target)
If rng Is Nothing Then Exit Sub 'no DV cells in Target
For Each c In rng.Cells
If c.Validation.Type = xlValidateList Then 'DV list?
Set rngList = Nothing
On Error Resume Next
'see if we can get a source range
Set rngList = Evaluate(c.Validation.Formula1)
On Error GoTo 0
If Not rngList Is Nothing Then
Application.EnableEvents = False
'find cell to link to
Set f = rngList.Find(c.Value, LookIn:=xlValues, lookat:=xlWhole)
If Not f Is Nothing Then
Application.EnableEvents = False
c.Formula = "='" & f.Parent.Name & "'!" & f.Address(0, 0)
Application.EnableEvents = True
End If
Else
Debug.Print "No source range for " & c.Address
End If
End If
Next c
End Sub