I'm detecting changes in the values of certain cells in an Excel spreadsheet like this...
Private Sub Worksheet_Change(ByVal Target As Range)
Dim cell As Range
Dim old_value As String
Dim new_value As String
For Each cell In Target
If Not (Intersect(cell, Range("cell_of_interest")) Is Nothing) Then
new_value = cell.Value
old_value = ' what here?
Call DoFoo (old_value, new_value)
End If
Next cell
End Sub
Assuming this isn't too bad a way of coding this, how do I get the value of the cell before the change?
Just a thought, but Have you tried using application.undo
This will set the values back again. You can then simply read the original value. It should not be too difficult to store the new values first, so you change them back again if you like.
I needed this feature and I did not like all the solutions above after trying most as they are either
Well I thought very hard about it and I completed a solution for a full UNDO,REDO history.
To capture the old value it is actually very easy and very fast.
My solution is to capture all values once the user open the sheet is open into a variable and it gets updated after each change. this variable will be used to check the old value of the cell. In the solutions above all of them used for loop. Actually there is way easier method.
To capture all the values I used this simple command
SheetStore = sh.UsedRange.Formula
Yeah, just that, Actually excel will return an array if the range is a multiple cells so we do not need to use FOR EACH command and it is very fast
The following sub is the full code which should be called in Workbook_SheetActivate. Another sub should be created to capture the changes. Like, I have a sub called "catchChanges" that runs on Workbook_SheetChange. It will capture the changes then save them on another a change history sheet. then runs UpdateCache to update the cache with the new values
' should be added at the top of the module
Private SheetStore() As Variant
Private SheetStoreName As String ' I use this variable to make sure that the changes I captures are in the same active sheet to prevent overwrite
Sub UpdateCache(sh As Object)
If sh.Name = ActiveSheet.Name Then ' update values only if the changed values are in the activesheet
SheetStoreName = sh.Name
ReDim SheetStore(1 To sh.UsedRange.Rows.count, 1 To sh.UsedRange.Columns.count) ' update the dimension of the array to match used range
SheetStore = sh.UsedRange.Formula
End If
End Sub
now to get the old value it is very easy as the array have the same address of cells
examples if we want cell D12 we can use the following
SheetStore(row_number,column_number)
'example
return = SheetStore(12,4)
' or the following showing how I used it.
set cell = activecell ' the cell that we want to find the old value for
newValue = cell.value ' you can ignore this line, it is just a demonstration
oldValue = SheetStore(cell.Row, cell.Column)
these are snippet explaining the method, I hope everyone like it
Here's a way I've used in the past. Please note that you have to add a reference to the Microsoft Scripting Runtime so you can use the Dictionary object - if you don't want to add that reference you can do this with Collections but they're slower and there's no elegant way to check .Exists (you have to trap the error).
Dim OldVals As New Dictionary
Private Sub Worksheet_Change(ByVal Target As Range)
Dim cell As Range
For Each cell In Target
If OldVals.Exists(cell.Address) Then
Debug.Print "New value of " & cell.Address & " is " & cell.Value & "; old value was " & OldVals(cell.Address)
Else
Debug.Print "No old value for " + cell.Address
End If
OldVals(cell.Address) = cell.Value
Next
End Sub
Like any similar method, this has its problems - first off, it won't know the "old" value until the value has actually been changed. To fix this you'd need to trap the Open event on the workbook and go through Sheet.UsedRange populating OldVals. Also, it will lose all its data if you reset the VBA project by stopping the debugger or some such.
I have an alternative solution for you. You could create a hidden worksheet to maintain the old values for your range of interest.
Private Sub Workbook_Open()
Dim hiddenSheet As Worksheet
Set hiddenSheet = Me.Worksheets.Add
hiddenSheet.Visible = xlSheetVeryHidden
hiddenSheet.Name = "HiddenSheet"
'Change Sheet1 to whatever sheet you're working with
Sheet1.UsedRange.Copy ThisWorkbook.Worksheets("HiddenSheet").Range(Sheet1.UsedRange.Address)
End Sub
Delete it when the workbook is closed...
Private Sub Workbook_BeforeClose(Cancel As Boolean)
Application.DisplayAlerts = False
Me.Worksheets("HiddenSheet").Delete
Application.DisplayAlerts = True
End Sub
And modify your Worksheet_Change event like so...
For Each cell In Target
If Not (Intersect(cell, Range("cell_of_interest")) Is Nothing) Then
new_value = cell.Value
' here's your "old" value...
old_value = ThisWorkbook.Worksheets("HiddenSheet").Range(cell.Address).Value
Call DoFoo(old_value, new_value)
End If
Next cell
' Update your "old" values...
ThisWorkbook.Worksheets("HiddenSheet").UsedRange.Clear
Me.UsedRange.Copy ThisWorkbook.Worksheets("HiddenSheet").Range(Me.UsedRange.Address)
Private Sub Worksheet_Change(ByVal Target As Range)
vNEW = Target.Value
aNEW = Target.Address
Application.EnableEvents = False
Application.Undo
vOLD = Target.Value
Target.Value = vNEW
Application.EnableEvents = True
End Sub
I have the same problem like you and luckily I have read the solution from this link: http://access-excel.tips/value-before-worksheet-change/
Dim oldValue As Variant
Private Sub Worksheet_SelectionChange(ByVal Target As Range)
oldValue = Target.Value
End Sub
Private Sub Worksheet_Change(ByVal Target As Range)
'do something with oldValue...
End Sub
Note: you must place oldValue
variable as a global variable so all subclasses can use it.
I had a need to capture and compare old values to the new values entered into a complex scheduling spreadsheet. I needed a general solution which worked even when the user changed many rows at the same time. The solution implemented a CLASS and a COLLECTION of that class.
The class: oldValue
Private pVal As Variant
Private pAdr As String
Public Property Get Adr() As String
Adr = pAdr
End Property
Public Property Let Adr(Value As String)
pAdr = Value
End Property
Public Property Get Val() As Variant
Val = pVal
End Property
Public Property Let Val(Value As Variant)
pVal = Value
End Property
There are three sheets in which i track cells. Each sheet gets its own collection as a global variable in the module named ProjectPlan as follows:
Public prepColl As Collection
Public preColl As Collection
Public postColl As Collection
Public migrColl As Collection
The InitDictionaries SUB is called out of worksheet.open to establish the collections.
Sub InitDictionaries()
Set prepColl = New Collection
Set preColl = New Collection
Set postColl = New Collection
Set migrColl = New Collection
End Sub
There are three modules used to manage each collection of oldValue objects they are Add, Exists, and Value.
Public Sub Add(ByRef rColl As Collection, ByVal sAdr As String, ByVal sVal As Variant)
Dim oval As oldValue
Set oval = New oldValue
oval.Adr = sAdr
oval.Val = sVal
rColl.Add oval, sAdr
End Sub
Public Function Exists(ByRef rColl As Collection, ByVal sAdr As String) As Boolean
Dim oReq As oldValue
On Error Resume Next
Set oReq = rColl(sAdr)
On Error GoTo 0
If oReq Is Nothing Then
Exists = False
Else
Exists = True
End If
End Function
Public Function Value(ByRef rColl As Collection, ByVal sAdr) As Variant
Dim oReq As oldValue
If Exists(rColl, sAdr) Then
Set oReq = rColl(sAdr)
Value = oReq.Val
Else
Value = ""
End If
End Function
The heavy lifting is done in the Worksheet_SelectionChange callback. One of the four is shown below. The only difference is the collection used in the ADD and EXIST calls.
Private Sub Worksheet_SelectionChange(ByVal Target As Range)
Dim mode As Range
Set mode = Worksheets("schedule").Range("PlanExecFlag")
If mode.Value = 2 Then
Dim c As Range
For Each c In Target
If Not ProjectPlan.Exists(prepColl, c.Address) Then
Call ProjectPlan.Add(prepColl, c.Address, c.Value)
End If
Next c
End If
End Sub
THe VALUE call is called out of code executed from the Worksheet_Change Callback for example. I need to assign the correct collection based on the sheet name:
Dim rColl As Collection
If sheetName = "Preparations" Then
Set rColl = prepColl
ElseIf sheetName = "Pre-Tasks" Then
Set rColl = preColl
ElseIf sheetName = "Migr-Tasks" Then
Set rColl = migrColl
ElseIf sheetName = "post-Tasks" Then
Set rColl = postColl
Else
End If
and then i am free to compute compare the some current value to the original value.
If Exists(rColl, Cell.Offset(0, 0).Address) Then
tsk_delay = Cell.Offset(0, 0).Value - Value(rColl, Cell.Offset(0, 0).Address)
Else
tsk_delay = 0
End If
Mark
an idea ...
ThisWorkbook
modulePublic LastCell As Range Private Sub Workbook_Open() Set LastCell = ActiveCell End Sub Private Sub Workbook_SheetSelectionChange(ByVal Sh As Object, ByVal Target As Range) Set oa = LastCell.Comment If Not oa Is Nothing Then LastCell.Comment.Delete End If Target.AddComment Target.Address Target.Comment.Visible = True Set LastCell = ActiveCell End Sub
You can use an event on the cell change to fire a macro that does the following:
vNew = Range("cellChanged").value
Application.EnableEvents = False
Application.Undo
vOld = Range("cellChanged").value
Range("cellChanged").value = vNew
Application.EnableEvents = True
I had to do it too. I found the solution from "Chris R" really good, but thought it could be more compatible in not adding any references. Chris, you talked about using Collection. So here is another solution using Collection. And it's not that slow, in my case. Also, with this solution, in adding the event "_SelectionChange", it's always working (no need of workbook_open).
Dim OldValues As New Collection
Private Sub Worksheet_SelectionChange(ByVal Target As Range)
'Copy old values
Set OldValues = Nothing
Dim c As Range
For Each c In Target
OldValues.Add c.Value, c.Address
Next c
End Sub
Private Sub Worksheet_Change(ByVal Target As Range)
On Local Error Resume Next ' To avoid error if the old value of the cell address you're looking for has not been copied
Dim c As Range
For Each c In Target
Debug.Print "New value of " & c.Address & " is " & c.Value & "; old value was " & OldValues(c.Address)
Next c
'Copy old values (in case you made any changes in previous lines of code)
Set OldValues = Nothing
For Each c In Target
OldValues.Add c.Value, c.Address
Next c
End Sub
I have read this old post, and I would like to provide another solution.
The problem with running Application.Undo is that Woksheet_Change runs again. We have the same problem when we restore.
To avoid that, I use a piece of code to avoid the second steps through Worksheet_Change.
Before we begin, we must create a Boolean static variable BlnAlreadyBeenHere, to tell Excel not to run Worksheet_Change again
Here you can see it:
Private Sub Worksheet_Change(ByVal Target As Range)
Static blnAlreadyBeenHere As Boolean
'This piece avoid to execute Worksheet_Change again
If blnAlreadyBeenHere Then
blnAlreadyBeenHere = False
Exit Sub
End If
'Now, we will store the old and new value
Dim vOldValue As Variant
Dim vNewValue As Variant
'To store new value
vNewValue = Target.Value
'Undo to retrieve old value
'To avoid new Worksheet_Change execution
blnAlreadyBeenHere = True
Application.Undo
'To store old value
vOldValue = Target.Value
'To rewrite new value
'To avoid new Worksheet_Change execution agein
blnAlreadyBeenHere = True
Target.Value = vNewValue
'Done! I've two vaules stored
Debug.Print vOldValue, vNewValue
End Sub
The advantage of this method is that it is not necessary to run Worksheet_SelectionChange.
If we want the routine to work from another module, we just have to take the declaration of the variable blnAlreadyBeenHere out of the routine, and declare it with Dim.
Same operation with vOldValue and vNewValue, in the header of a module
Dim blnAlreadyBeenHere As Boolean
Dim vOldValue As Variant
Dim vNewValue As Variant
try this, it will not work for the first selection, then it will work nice :)
Private Sub Worksheet_SelectionChange(ByVal Target As Range)
On Error GoTo 10
If Target.Count > 1 Then GoTo 10
Target.Value = lastcel(Target.Value)
10
End Sub
Function lastcel(lC_vAl As String) As String
Static vlu
lastcel = vlu
vlu = lC_vAl
End Function
Let's first see how to detect and save the value of a single cell of interest. Suppose Worksheets(1).Range("B1")
is your cell of interest. In a normal module, use this:
Option Explicit
Public StorageArray(0 to 1) As Variant
' Declare a module-level variable, which will not lose its scope as
' long as the codes are running, thus performing as a storage place.
' This is a one-dimensional array.
' The first element stores the "old value", and
' the second element stores the "new value"
Sub SaveToStorageArray()
' ACTION
StorageArray(0) = StorageArray(1)
' Transfer the previous new value to the "old value"
StorageArray(1) = Worksheets(1).Range("B1").value
' Store the latest new value in Range("B1") to the "new value"
' OUTPUT DEMONSTRATION (Optional)
' Results are presented in the Immediate Window.
Debug.Print "Old value:" & vbTab & StorageArray(0)
Debug.Print "New value:" & vbTab & StorageArray(1) & vbCrLf
End Sub
Then in the module of Worksheets(1):
Option Explicit
Private HasBeenActivatedBefore as Boolean
' Boolean variables have the default value of False.
' This is a module-level variable, which will not lose its scope as
' long as the codes are running.
Private Sub Worksheet_Activate()
If HasBeenActivatedBefore = False then
' If the Worksheet has not been activated before, initialize the
' StorageArray as follows.
StorageArray(1) = Me.Range("B1")
' When the Worksheets(1) is activated, store the current value
' of Range("B1") to the "new value", before the
' Worksheet_Change event occurs.
HasBeenActivatedBefore = True
' Set this parameter to True, so that the contents
' of this if block won't be evaluated again. Therefore,
' the initialization process above will only be executed
' once.
End If
End Sub
Private Sub Worksheet_Change(ByVal Target As Range)
If Not Intersect(Target, Me.Range("B1")) Is Nothing then
Call SaveToStorageArray
' Only perform the transfer of old and new values when
' the cell of interest is being changed.
End If
End Sub
This will capture the change of the Worksheets(1).Range("B1")
, whether the change is due to the user actively selecting that cell on the Worksheet and changing the value, or due to other VBA codes that change the value of Worksheets(1).Range("B1")
.
Since we have declared the variable StorageArray
as public, you can reference its latest value in other modules in the same VBA project.
To expand our scope to the detection and saving the values of multiple cells of interest, you need to:
StorageArray
as a two-dimensional array, with the number of rows equal to the number of cells you are monitoring.Sub SaveToStorageArray
procedure to a more general Sub SaveToStorageArray(TargetSingleCell as Range)
and change the
relevant codes.Private Sub Worksheet_Change
procedure to accommodate the monitoring of those multiple cells.Appendix: For more information on the lifetime of variables, please refer to: https://msdn.microsoft.com/en-us/library/office/gg278427.aspx
In response to Matt Roy answer, I found this option a great response, although I couldn't post as such with my current rating. :(
However, while taking the opportunity to post my thoughts on his response, I thought I would take the opportunity to include a small modification. Just compare code to see.
So thanks to Matt Roy for bringing this code to our attention, and Chris.R for posting original code.
Dim OldValues As New Collection
Private Sub Worksheet_SelectionChange(ByVal Target As Range)
'>> Prevent user from multiple selection before any changes:
If Selection.Cells.Count > 1 Then
MsgBox "Sorry, multiple selections are not allowed.", vbCritical
ActiveCell.Select
Exit Sub
End If
'Copy old values
Set OldValues = Nothing
Dim c As Range
For Each c In Target
OldValues.Add c.Value, c.Address
Next c
End Sub
Private Sub Worksheet_Change(ByVal Target As Range)
On Error Resume Next
On Local Error Resume Next ' To avoid error if the old value of the cell address you're looking for has not been copied
Dim c As Range
For Each c In Target
If OldValues(c.Address) <> "" And c.Value <> "" Then 'both Oldvalue and NewValue are Not Empty
Debug.Print "New value of " & c.Address & " is " & c.Value & "; old value was " & OldValues(c.Address)
ElseIf OldValues(c.Address) = "" And c.Value = "" Then 'both Oldvalue and NewValue are Empty
Debug.Print "New value of " & c.Address & " is Empty " & c.Value & "; old value is Empty" & OldValues(c.Address)
ElseIf OldValues(c.Address) <> "" And c.Value = "" Then 'Oldvalue is Empty and NewValue is Not Empty
Debug.Print "New value of " & c.Address & " is Empty" & c.Value & "; old value was " & OldValues(c.Address)
ElseIf OldValues(c.Address) = "" And c.Value <> "" Then 'Oldvalue is Not Empty and NewValue is Empty
Debug.Print "New value of " & c.Address & " is " & c.Value & "; old value is Empty" & OldValues(c.Address)
End If
Next c
'Copy old values (in case you made any changes in previous lines of code)
Set OldValues = Nothing
For Each c In Target
OldValues.Add c.Value, c.Address
Next c
Place the following in the CODE MODULE of a WORKSHEET to track the last value for every cell in the used range:
Option Explicit
Private r As Range
Private Const d = "||"
Public Function ValueLast(r As Range)
On Error Resume Next
ValueLast = Split(r.ID, d)(1)
End Function
Private Sub Worksheet_Activate()
For Each r In Me.UsedRange: Record r: Next
End Sub
Private Sub Worksheet_Change(ByVal Target As Range)
For Each r In Target: Record r: Next
End Sub
Private Sub Record(r)
r.ID = r.Value & d & Split(r.ID, d)(0)
End Sub
And that's it.
This solution uses the obscure and almost never used Range.ID property, which allows the old values to persist when the workbook is saved and closed.
At any time you can get at the old value of a cell and it will indeed be different than a new current value:
With Sheet1
MsgBox .[a1].Value
MsgBox .ValueLast(.[a1])
End With
Using Static
will solve your problem (with some other stuff to initialize old_value
properly:
Private Sub Worksheet_Change(ByVal Target As Range)
Static old_value As String
Dim inited as Boolean 'Used to detect first call and fill old_value
Dim new_value As String
If Not Intersect(cell, Range("cell_of_interest")) Is Nothing Then
new_value = Range("cell_of_interest").Value
If Not inited Then
inited = True
Else
Call DoFoo (old_value, new_value)
End If
old_value = new_value
Next cell
End Sub
In workbook code, force call of Worksheet_change
to fill old_value
:
Private Sub Private Sub Workbook_Open()
SheetX.Worksheet_Change SheetX.Range("cell_of_interest")
End Sub
Note, however, that ANY solution based in VBA variables (including dictionary and another more sophisticate methods) will fail if you stop (Reset) running code (eg. while creating new macros, debugging some code, ...). To avoid such, consider using alternative storage methods (hidden worksheet, for example).
Source: Stackoverflow.com