Checking Excel 2003 data validation

The following bit of VBA will highlight any cells in a sheet with data validation errors:

Sub CheckValidation(sht As Worksheet)
Dim cell As Range
Dim rngDV As Range
Dim dvError As Boolean

On Error Resume Next
Set rngDV = sht.UsedRange.SpecialCells(xlCellTypeAllValidation)
On Error GoTo 0

If rngDV Is Nothing Then
    sht.ClearCircles
Else
    dvError = False
    For Each cell In rngDV
        If Not cell.Validation.Value Then
            dvError = True
            Exit For
        End If
    Next

    If dvError Then
        sht.CircleInvalid
        sht.Activate
    Else
        sht.ClearCircles
    End If
End If
End Sub

However, the "For Each" loop runs reall开发者_开发问答y slowly in sheets with a lot of data validation.

Does anyone know of a way to avoid the "For Each" loop, or speed it up somehow?

I would have thought that the following would be equivalent to set the value of 'dvError':

dvError = Not rngDV.Validation.Value

But for some reason, rngDV.Validation.Value is true even when there are data validation errors.

I had a slightly different requirement where I wanted to restrict the values entered by a user to a valid date range or the text "ASAP" which I resolved using the following;

Private Sub Worksheet_Change(ByVal Target As Range)
    Dim sErr        As String
    Dim sProc       As String

    On Error GoTo ErrHandler

    Application.EnableEvents = False

    Select Case Target.Column
    Case 11
        sProc = "Validate Date"

        'The value must be a date between "1 Nov 2011" and "30 Jun 2012" or "ASAP"...
        If IsDate(Target.Value) Then
            If Target.Value < CDate("2011-11-01") _
            Or Target.Value > CDate("2012-06-30") Then
                Err.Raise vbObjectError + 1
            End If
        ElseIf LCase(Target.Value) = "asap" Then
            Target.Value = "ASAP"
        ElseIf Len(Trim(Target.Value)) = 0 Then
            Target.Value = vbNullString
        Else
            Err.Raise vbObjectError + 1
        End If
    End Select

ErrHandler:
    Select Case Err.Number
    Case 0
        'Nothing to do...
    Case vbObjectError + 1
        sErr = "The Date must be between ""1 Nov 2011"" and ""30 Jun 2012"" or equal ""ASAP""."
    Case Else
        sErr = Err.Description
    End Select

    If Len(Trim(sErr)) > 0 Then
        Target.Select
        MsgBox sErr, vbInformation + vbOKOnly, sProc
        Target.Value = vbNullString
    End If

    Application.EnableEvents = True
End Sub

Tried your code and it's working quite fast with 4536 cells containing validations - as you are rightly breaking your FOR at the first occurence of an unvalidated cell

I tried to measure time at various points of your code by following:

Dim Tick As Variant
Tick = Now()
' ... code
Debug.Print "ValCount", rngDV.Cells.Count ' just to see how many cells are in that range
' ... code
Debug.Print "Pt1",  (Now() - Tick) * 86400000 'display milliseconds
' ... code
Debug.Print "Pt2",  (Now() - Tick) * 86400000 'display milliseconds
' ... code
Debug.Print "Pt3",  (Now() - Tick) * 86400000 'display milliseconds
' etc.

and got a not measureable delay (except when stepping thru debugger with F8 - of course)

As a generic hint ... try to find out where exactly your code is slow and let's take it from there.