Comment Used To Track Changes - excel

Question

I have encountered a few issues with some code in VBA. I am trying to have the changes made to a cells on an excel sheet show up in comments on the cell the change was made to and I wish for these changes to be stored in a list so I can view them all later. I have tried lots of different pieces of code I have found to try and implement it into the code but none have worked.
Any ideas on how to get this to work?
Worksheet
The below code is what I am currently using
Private Sub Worksheet_Change(ByVal Target As Range)
Dim Adding As Boolean, Finding As Boolean, Subtracting As Boolean
Dim f As Range, v
Select Case Target.Address(True, True)
Case "$A$4": Adding = True
Case "$C$4": Subtracting = True
Case "$E$4": Finding = True
Case Else: Exit Sub
End Select
v = Trim(Target.Value)
If Len(v) = 0 Then Exit Sub
Set f = Me.Range("C8").Resize(1000, 1).Find(v, lookat:=xlWhole)
If Adding Then
If f Is Nothing Then
'not found: add as new row
Set f = Me.Cells(Rows.Count, 3).End(xlUp).Offset(1, 0)
f.Value = v
End If
f.Offset(0, 1).Value = f.Offset(0, 1).Value + 1
doDate f.Offset(0, 2)
Target.Value = ""
ElseIf Subtracting Then
If f Is Nothing Then
MsgBox v & " not found for subtraction!"
Else
f.Offset(0, 1).Value = f.Offset(0, 1).Value - 1
doDate f.Offset(0, 3)
Target.Value = ""
End If
Else 'finding
If Not f Is Nothing Then
f.EntireRow.Select
Target.Value = ""
Else
MsgBox v & " not found."
End If
End If
If Adding Or Subtracting Then Target.Select
End Sub
Sub doDate(c As Range)
With c
.NumberFormat = "m/d/yyyy h:mm AM/PM"
.Value = Now
End With
End Sub
I have implemented a few formulas on the worksheet but don't see any reason why it would matter in this situation since they only track quantity of items with the same unique identifier.
I also tried some code that added comments to the cells as they were changed that worked but always returned the previous cell value as blank. It is not actually added into the current code though.
Option Explicit
Public preValue As Variant
Private Sub Worksheet_Change(ByVal Target As Range)
If Target.Count > 1 Then Exit Sub
Target.ClearComments
Target.AddComment.Text Text:="Previous Value was " & preValue & Chr(10) & "Revised " & Format(Date, "mm-dd-yyyy") & Chr(10) & "By " & Environ("UserName")
End Sub
Private Sub Worksheet_SelectionChange(ByVal Target As Range)
If Target.Count > 1 Then Exit Sub
If Target = "" Then
preValue = "a blank"
Else: preValue = Target.Value
End If
End Sub

Answer 1

By and large, the code below should do what you want. I marveled at your use of A4 and C4 to express addition and subtraction. As it is, whatever you change in those two cells, apart from clearing them, will result in a quantity of 1 being added or subtracted. I would have expected that a quantity must be entered there which is processed. If the quantity is fixed at 1 the system appears too elaborate.
Anyway, here's the code. I guess you'll be able to modify it to better suit your needs.
Private Sub Worksheet_Change(ByVal Target As Range)
' 038
Dim LookUp As Variant ' subject
Dim Action As Variant ' add = 1, subtract = -1, find = 2
Dim Fnd As Range ' Result of Find method
Dim Txt As String ' comment text
With Target
If (.Row <> 4) Or (.CountLarge > 1) Then Exit Sub
LookUp = Cells(4, "E").Value
On Error Resume Next
Action = Array(0, 1, 0, -1, 0, 2)(.Column)
End With
If Action And (LookUp <> "") Then
' C8 to end of column C
With Range(Cells(8, "C"), Cells(Rows.Count, "C").End(xlUp))
Set Fnd = .Find(LookUp, .Cells(.Cells.Count), xlValues, xlWhole, xlByRows)
End With
End If
If Fnd Is Nothing Then
Select Case Action
Case -1
MsgBox """" & LookUp & """ not found.", vbInformation, "Can't subtract"
Action = -2
Case 2
MsgBox """" & LookUp & """ not found.", vbInformation, "No record"
Action = -2
Case Else
Set Fnd = Cells(Rows.Count, "C").End(xlUp).Offset(1)
Fnd.Value = LookUp
End Select
End If
With Fnd
If Abs(Action) <> 2 Then
With .Offset(0, 1)
If .Comment Is Nothing Then
.AddComment
Else
Txt = Chr(10)
End If
Txt = "Previous Qty = " & .Value & Chr(10) & _
"Revised " & Format(Date, "mm-dd-yyyy") & Chr(10) & _
"by " & Environ("UserName") & Txt
.Comment.Text Txt, 1, False
.Value = Val(.Value) + Action
With .Offset(0, 2)
.NumberFormat = "m/d/yyyy h:mm AM/PM"
.Value = Now
End With
End With
ElseIf Action = 2 Then
.EntireRow.Select
End If
End With
If Action <> 2 Then Target.Select
End Sub