Private Sub Worksheet_Calculate() [closed]

Answer 1

UPDATE

Instead of highlighting the cells, do you know how to insert a comment in each cell whenever the cell value changes? I would like to comment to say, "Changed cell from 20 to 30".

Try this code (may be time consuming for big ranges with formulas):

in Code module (standart module):

Public cVals As New Dictionary

Sub populateDict()
    Dim rng As Range, c As Range

    With ThisWorkbook.Worksheets("Sheet1")
        Set rng = Intersect(.UsedRange, .Range("CP:CV"))
        If rng Is Nothing Then Exit Sub
        For Each c In rng
            cVals(c.Address) = c.Text
        Next c
        .Calculate
    End With
End Sub

in ThisWorkbook module:

Private Sub Workbook_Open()
    Application.Calculation = xlCalculationManual
    Call populateDict
    Application.Calculation = xlCalculationAutomatic
End Sub

in Sheet module:

Private Sub Worksheet_Calculate()
    Dim rng As Range, c As Range
    Dim rngToColor As Range

    On Error GoTo ErrorHandler

    Application.EnableEvents = False
    'get only used part of the sheet
    Set rng = Intersect(Me.UsedRange, Me.Range("CP:CV"))
    If rng Is Nothing Then GoTo ExitHere ' if there is no formulas in CP:CV - exit from sub

    'reset color for all cells
    rng.Interior.Color = xlNone
    For Each c In rng
        'check if previous value of this cell not equal to current value
        If cVals(c.Address) <> c.Text Then
            'if so (they're not equal), remember this cell
            c.ClearComments
            c.AddComment Text:="Changed value from '" & cVals(c.Address) & "' to '" & c.Text & "'"
        End If
        'store current value of cell in dictionary (with key=cell address)
        cVals(c.Address) = c.Text
    Next c

ExitHere:
    Application.EnableEvents = True
    Exit Sub
ErrorHandler:
    Resume ExitHere
End Sub

Note that I'm uisng Dictionary object. For working with Dictionary object you should add reference to Microsoft Scripting Runtime library. Go to Tools->References and select Microsoft Scripting Runtime library: