# Check if a range in Excel contains DataValidation

One of the answers to Determine if cell contains data validation got me thinking about an edge case I needed to solve. If cell happens to be a multi-cell range what's the best way to answer? The answer below returns False if the range contains both a cell with and without validation.

Function HasValidation(cell As Range) As Boolean
Dim t: t = Null

On Error Resume Next
t = cell.Validation.Type
On Error GoTo 0

HasValidation = Not IsNull(t)
End Function


The answer I arrived at allows for non-contiguous ranges. I chose Variant as the return type in the case that there's a mix of validated and non-validated cells. Since it's neither True nor False a Null seemed the best fit.

Public Function HasValidation(ByVal cell As Range) As Variant
Dim tempVariable As Variant
If cell.Cells.Count > 1 Then
On Error Resume Next

Dim singleCell As Range
For Each singleCell In cell
tempVariable = Empty
tempVariable = singleCell.Validation.Type

If IsEmpty(tempVariable) Then
Dim cellWithoutValidationFound As Boolean
cellWithoutValidationFound = True
Else
Dim cellWithValidationFound As Boolean
cellWithValidationFound = True
End If

If cellWithValidationFound And cellWithoutValidationFound Then
On Error GoTo 0
HasValidation = Null
Exit Function
End If
Next

HasValidation = cellWithValidationFound
Else
tempVariable = Null
tempVariable = cell.Validation.Type
HasValidation = IsNull(tempVariable)
End If
End Function

• No. I was focusing on the multi-cell option that I neglected to properly update a single-cell range. – IvenBach Apr 26 '18 at 0:52

I'd recommend caution re: using On Error statements in utility functions like this. Any custom error handling in the main procedure (ie "On Error GoTo lineNum") will be overwritten by this function, so you'll have to remember to manually change it back any time you use the function in a procedure with custom error handling.

My advice would be to pick a personal rule-- either "Never use On Error statements in utility functions, only in main procedures" or "Only use On Error statements in utility functions, never in main procedures"-- and stick to it.

If you do use them, make sure that you switch back to On Error GoTo 0 for all exits from the function. In the first portion of the "IF" block in your current code, you only switch back if the function returns null:

On Error Resume Next
Dim singleCell As Range
For Each singleCell In cell
'...do stuff, then

If cellWithValidationFound And cellWithoutValidationFound Then
On Error GoTo 0
HasValidation = Null
Exit Function
End If
Next

'On Error GoTo 0 needs to be added here
HasValidation = cellWithValidationFound


In this case, it's possible to avoid the "On Error" statements entirely by using the SpecialCells and Intersect methods. Only caveat is that it assumes that your range's parent worksheet contains at least one blank cell:

Function hasValidation(rng As Range) As Variant

'Find first empty cell in ws and add validation
'This ensures that at least 1 cell in ws contains validation
Dim emptyCell As Range
Set emptyCell = rng.Parent.Cells.SpecialCells(xlCellTypeBlanks).Cells(1)

'Get range of all cells in ws with validation, then remove validation from empty cell
Dim validationCells As Range
Set validationCells = rng.Parent.Cells.SpecialCells(xlCellTypeAllValidation)
emptyCell.Validation.Delete

'Get intersection of validation cells and range being tested
Dim rngUnion As Range
Set rngUnion = Intersect(rng, validationCells)

'Determine whether entire/partial range has validation and return value
If rngUnion Is Nothing Then
hasValidation = False
ElseIf rngUnion.Count = rng.Count Then
hasValidation = True
Else
hasValidation = Null
End If

End Function


It'd be possible to design a slightly safer version that accounts for sheets with no blank cells, but that scenario is so unlikely that it's probably not worth the effort.

EDIT: Actually, it turns out that Range.SpecialCells(xlCellTypeBlanks) is way worse than I thought. Not only is it obscenely slow for large ranges, it also only searches the Used Range, not the entire sheet. So you may have no option but to use error handling.

Luckily, you can use the same basic format while incorporating On Error. Since it uses Intersect instead of looping through cells, it should be faster than your version. Also, rather than returning Null in mixed cases, it uses optional parameter that alters how the function treats ranges with a mix of validation/no validation. That's just a stylistic preference, I'm not a big fan of Null. Here's my final version:

Function hasValidation(rng As Range, Optional entireRange As Boolean = False) As Boolean

'Get range of all cells in sheet containing validation
On Error Resume Next
Dim validationCells As Range
Set validationCells = rng.Parent.Cells.SpecialCells(xlCellTypeAllValidation)
On Error GoTo 0

'If no cells contain validation, return False and exit
If validationCells Is Nothing Then
hasValidation = False
Exit Function
End If

'Get intersection of validation cells and range being tested
Dim rngUnion As Range
Set rngUnion = Intersect(rng, validationCells)

'Determine whether entire/partial range has validation and return value
If rngUnion Is Nothing Then
hasValidation = False
Else
hasValidation = IIf(rngUnion.Count = rng.Count, True, Not entireRange)
End If

End Function


I would suggest that HasValidation() returns either True or False, not maybe?...

Option Explicit

Public Function HasValidation(ByVal rng As Range) As Boolean
Dim itHas As Boolean, eID As Long, eSRC As String, eDESC As String

If Err.Number <> 0 Then
eID = Err.Number
eSRC = Err.Source
eDESC = Err.Description
Err.Clear
End If

On Error Resume Next
If Not rng Is Nothing Then
itHas = Not Intersect(rng.SpecialCells(xlCellTypeAllValidation), rng) Is Nothing
End If

If Err.Number <> 0 Or eID <> 0 Then
If eID = 0 Then Err.Clear Else Err.Raise eID, eSRC, eDESC
End If
HasValidation = itHas
End Function


Or GetValidationRange() that returns a Range or Nothing

Public Function GetValidationRange(ByVal rng As Range) As Range
Dim vRng As Range, eID As Long, eSRC As String, eDESC As String

If Err.Number <> 0 Then
eID = Err.Number
eSRC = Err.Source
eDESC = Err.Description
Err.Clear
End If

On Error Resume Next
If Not rng Is Nothing Then
Set vRng = Intersect(rng.SpecialCells(xlCellTypeAllValidation), rng)
End If

If Err.Number <> 0 Or eID <> 0 Then
If eID = 0 Then Err.Clear Else Err.Raise eID, eSRC, eDESC
End If
Set GetValidationRange = vRng
End Function


.

• The parameter name (cell) implies that it expects a single cell
• The Null return type can cause issues (not very used in normal operations)