Excel UDF detecting page breaks? - excel

I'm trying to write a UDF that returns whether the cell is at a page break.
So far I have this:
Function pbreak() As Boolean
' Application.Volatile
pbreak = False
Dim ra As Range
Set ra = Application.Caller
With ra
For i = 1 To .Worksheet.HPageBreaks.Count
If .Worksheet.HPageBreaks(i).Location.Row = .Row Then
pbreak = True
End If
Next
End With
End Function
This returns a #VALUE error. I've tried debugging it, HPageBreaks.Count returns 3 (and there are 3 page breaks), but HPageBreaks(i) yields an "index out of range"-error for all pagebreaks that are below the current cell .
Is this a bug (ie .Count is wrong), or is there some special behavior with page breaks that I am missing?
Is there a way to fix this (preferably without resorting to on error resume next)?
Thanks
Martin

Option Explicit
Function pbreak() As Boolean
' Application.Volatile
Dim i As Integer 'the missing line
pbreak = False
Dim ra As Range
Set ra = Application.Caller
With ra
For i = 1 To .Worksheet.HPageBreaks.Count
If .Worksheet.HPageBreaks(i).Location.Row <= .Row Then
If .Worksheet.HPageBreaks(i).Location.Row = .Row Then
pbreak = True
'exit the function once a page break is found.
Exit Function
End If
Else
Exit Function
End If
Next
End With
End Function
EDIT: Always use Option Explicit & compile the code before using it.
Use of Exit Function inside the loop is to prevent the code from running it further, once the result is known.

Related

Custom lookup using search in VBA

I am not sure, how to fix this function.
if Isnumber(search) is true, then get value from lookup_table
after 2nd round, it ends
Image of excel data
Function Slookup(lookup_value As String, lookup_table As Range) As String
Dim i As Integer
On Error GoTo Err
Dim valuetxt As Boolean
Dim cc As Integer
cc = lookup_table.Rows.Count
For i = 1 To cc
valuetxt = IsError(Application.WorksheetFunction.Search(lookup_table.Cells(i, 1), lookup_value))
If Not valuetxt Then
Slookup = lookup_table.Cells(i, 2)
Exit Function
End If
Slookup = ExcelError.ExcelErrorNA
Err:
Next i
End Function
Tim Williams is correct in noting that IsError() cannot trap a run-time error (1004). So, your IsError() isn't doing much, except providing the necessary False for If Not valuetxt Then when there is no error.
The real problem lies with the fact that your error handler stays within the loop. On Error GoTo Err will not be triggered once you are already inside Err:. The code fails at the third example, because it is the second time you run into an error.
I.e. in your third example, you'll get an error at
IsError(Application.WorksheetFunction.Search("A", "E G F")) and are moved to Err:. However, you're not exiting the loop, so now you'll get another error at IsError(Application.WorksheetFunction.Search("B", "E G F")) and the thing breaks down. (So, your second example actually also encountered an error, but it never encountered another.)
You can fix this as follows:
Function SlookupAdj(lookup_value As String, lookup_table As Range) As String
Dim i As Integer
Dim valuetxt As Boolean
Dim cc As Integer
cc = lookup_table.Rows.Count
For i = 1 To cc
On Error Resume Next
valuetxt = IsError(Application.WorksheetFunction.Search(lookup_table.Cells(i, 1), lookup_value))
If Err Then
Err.Clear
Else
If Not valuetxt Then
SlookupAdj = lookup_table.Cells(i, 2)
Exit Function
End If
End If
SlookupAdj = ExcelError.ExcelErrorNA
Next i
End Function
In this modified code, we run into the same error, but simply skip it, deal with the fact that there is an error (If Err Then), clear it, and then make sure we never reach the evaluation of If Not valuetxt Then.
Again, Tim Williams is correct in noting that the thing you are trying to do, is more easily accomplished using Instr(). Like so:
Function InstrMethod(lookup_value As String, lookup_table As Range) As String
Dim i As Integer
Dim valuetxt As Boolean
Dim cc As Integer
cc = lookup_table.Rows.Count
For i = 1 To cc
valuetxt = InStr(lookup_value, lookup_table.Cells(i, 1))
If valuetxt Then
InstrMethod = lookup_table.Cells(i, 2)
Exit Function
End If
Next i
End Function

Error handling in a loop using Resume Next

as a newcomer to VBA any help would be appreciated. The basic point of my program is to loop through columns of the spreadsheet and count the number of non-blank cells in each column, within a specified range.
Here is an example of what my spreadsheet looks like.
1
2
3
1
thing
2
thing
3
thing
When all the cells in the column are blank, VBA throws out a 1004 error, no cells found. What I want to do is say, if a 1004 error occurs, set the count of the non-blank cells (nonBlank = 0) equal to zero, and if no error occurs, count normally. In something like Python, I'd use try/except. Here is my attempt.
For i = 1 To 3
On Error Resume Next
Set selec_cells = Sheet1.Range(Sheet1.Cells(FirstRow, i), Sheet1.Cells(LastRow, i)).SpecialCells(xlCellTypeVisible).Cells.SpecialCells(xlCellTypeConstants)
If Err.Number <> 1004 Then
nonBlank = 0
Else
nonBlank = selec_cells.Count
End If
On Error GoTo -1
Next i
My issue is, when I run this code, it spits out 0 every time, even though column 2 should return 3. Thank you!
Edit: selec_cells is what throws out the error.
Error Handling
There is no On Error Goto -1 in VBA, it's a VB thing (those are links to different pages). A tip would be if you google VBA stuff, just put VBA in front of what you're looking for.
When using On Error Resume Next (defer error trapping), you should 'apply' it on a line or two maximally and 'close' with On Error Goto 0 (disable error trapping) or with another error handler.
Your usage of On Error Resume Next is unacceptable because in this particular case we can test the range: 1. defer error handling, 2. try to set the range, 3. disable error handling. If there was an error the range will not be set hence If Not rg Is Nothing Then which could be translated to something like 'If rg Is Something Then' (double negation) or If a reference to a range has been created Then.
The second solution illustrates a case where the main error handler is handling all errors except the SpecialCells error which has its own error handler. Resume Next means continue with the line after the line where the error occurred. Note the Exit Sub line and note Resume ProcExit where the code is redirected to a label.
The following illustrates two ways how you could handle this. At this stage, I would suggest you use the first one and remember to use the 'closing' On Error Goto 0 whenever you use On Error Resume Next (a line or two).
The Code
Option Explicit
Sub testOnErrorResumeNext()
Const FirstRow As Long = 2
Const LastRow As Long = 11
Dim rg As Range ' ... additionally means 'Set rg = Nothing'.
Dim nonBlank As Long ' ... additionally means 'nonBlank = 0'.
Dim j As Long
For j = 1 To 3 ' Since it's a column counter, 'j' or 'c' seems preferred.
' Since you're in a loop, you need the following line.
Set rg = Nothing
On Error Resume Next
Set rg = Sheet1.Range(Sheet1.Cells(FirstRow, j), _
Sheet1.Cells(LastRow, j)).SpecialCells(xlCellTypeVisible) _
.Cells.SpecialCells(xlCellTypeConstants)
On Error GoTo 0
If Not rg Is Nothing Then
nonBlank = rg.Cells.Count
Else
' Since you're in a loop, you need the following line.
nonBlank = 0
End If
Debug.Print nonBlank
Next j
End Sub
Sub testOnError()
On Error GoTo clearError
Const FirstRow As Long = 2
Const LastRow As Long = 11
Dim rg As Range ' ... additionally means 'Set rg = Nothing'.
Dim nonBlank As Long ' ... additionally means 'nonBlank = 0'.
Dim j As Long
For j = 1 To 3 ' Since it's a column counter, 'j' or 'c' seems preferred.
' Since you're in a loop, you need the following line.
Set rg = Nothing
On Error GoTo SpecialCellsHandler
Set rg = Sheet1.Range(Sheet1.Cells(FirstRow, j), _
Sheet1.Cells(LastRow, j)).SpecialCells(xlCellTypeVisible) _
.Cells.SpecialCells(xlCellTypeConstants)
On Error GoTo clearError
If Not rg Is Nothing Then
nonBlank = rg.Cells.Count
End If
Debug.Print nonBlank
Next j
ProcExit:
Exit Sub ' Note this.
SpecialCellsHandler:
' Since you're in a loop, you need the following line.
nonBlank = 0
Resume Next
clearError:
MsgBox "Run-time error '" & Err.Number & "': " & Err.Description
Resume ProcExit
End Sub
My preference is, wherever possible, to encapsulate the line of code that may cause an error in its own function. The function returns true or false to indicate whether or not there is an error and an out parameter is used to return the value that you want.
This keeps the error testing confined within a very short well defined function.
Sub ttest()
Dim mySheet As Excel.Worksheet
Set mySheet = ThisWorkbook.Sheet1
Dim myIndex As Long
Dim myNonBlank as long
For myIndex = 1 To 3
If AllCellsAreBlank(mySheet.Range(ThisWorkbook.Sheet1.Cells(myFirstRow, myIndex), mySheet.Cells(myLastRow, myIndex)), myIndex, mySelectCells) Then
myNonBlank = 0
Else
myNonBlank = mySelectCells.Count
End If
Next
End Sub
Public Function AllCellsAreBlank(ByRef ipRange As Excel.Range, ByVal ipIndex As Long, ByRef opSelectCells As Range) As Boolean
On Error Resume Next
set opSelectCells = ipRange.SpecialCells(xlCellTypeVisible).Cells.SpecialCells(xlCellTypeConstants)
AllCellsAreBlank = Err.Number <> 0
On Error GoTo 0
End Function
For reference the prefixes I use are
ip: for an input only parameter
iop: for an input parameters that will be changed by the method
op: for a parameter only used to return a value
my: any variable declared within a Method.
I's also suggest you acquire the habit of meaningful descriptive names, myRow, myCol are much more meaningful than i,j, and of ensuring you use fully qualified references rather than the implicit use of the activesheet.

Find names in ActiveWorkbook.Names

I want to find specific names in my workbook.names.
These names begin with "NameToFind" and the end of the names are ID numbers.
The goal is to find all ID.
For Each n In ActiveWorkbook.Names
If Left(n.Name, NameToFindLen) = NameToFind Then
(...)
end if
next n
I have a lot of names and this search is too long. How could I optimize this code?
Try and see if this method is faster for you.
If you want to run this test case, add a named range "name1"
Then run test --- should show true in the immediate window.
If you haven't made the named range, should show false.
Option Explicit
Function IsName(NameOfName) As Boolean
Dim check As Name
On Error Resume Next
Set check = ActiveWorkbook.Names(NameOfName)
On Error GoTo 0
If check Is Nothing Then
IsName = False
Else
IsName = True
End If
End Function
Sub TestIsName()
Dim test As Boolean
test = IsName("name1")
Debug.Print (test)
End Sub
I have a little simpler solution
Function isName(NameofName) As Boolean
Dim n As name
isName = False
For Each n In ActiveWorkbook.Names
If n.name = NameofName Then isName = True
Exit Function ' not needed, but speeds up process for workbooks with a lot of names
Next n
End Function

Excel VBA check if named range is set

I'm trying to determine if a named range has been set via VBA. The named range is called LoadedToken and essentially is loaded when a user clicks a particular button. I use this as proof that initialisation has taken place.
I have a function to check if this has taken place:
Function ToolIsEnabled()
' We check if the R2A add-in has been loaded by detecting the named range
If ActiveWorkbook.Names("LoadedToken") Is Nothing Then
ToolIsEnabled = False
Else
ToolIsEnabled = True
End If
End Function
and I get an application error. Of course, the VBA is incorrect. However how can I actually accomplish this?!
Sub Test()
Debug.Print IsNamedRange("Bumsti")
End Sub
Function IsNamedRange(RName As String) As Boolean
Dim N As Name
IsNamedRange = False
For Each N In ActiveWorkbook.Names
If N.Name = RName Then
IsNamedRange = True
Exit For
End If
Next
End Function
Usage in OP context could be
' ...
If IsNamedRange("LoadedToken") Then
' ...
End If
' ...
or - if a program specific Bool needs to be set
' ...
Dim IsTokenLoaded as Boolean
IsTokenLoaded = IsNamedRange("LoadedToken")
' ...
Both constructs make it pretty clear in the source code what you are aiming for.
You can achieve this by using error handling:
Function ToolIsEnabled() As Boolean
Dim rng As Range
On Error Resume Next
Set rng = ActiveWorkbook.Range("LoadedToken")
On Error GoTo 0
ToolIsEnabled = Not rng is Nothing
End Function
This will check either in ThisWorkbook or a named workbook and return TRUE/FALSE.
Sub Test()
MsgBox NamedRangeExists("SomeName")
MsgBox NamedRangeExists("SomeOtherName", Workbooks("Book1.xls"))
End Sub
Public Function NamedRangeExists(sName As String, Optional Book As Workbook) As Boolean
On Error Resume Next
If Book Is Nothing Then
Set Book = ThisWorkbook
End If
NamedRangeExists = Book.Names(sName).Index <> (Err.Number = 0)
On Error GoTo 0
End Function
Edit:
A shorter version if it's only going to look in ThisWorkbook:
Public Function NamedRangeExists(sName As String) As Boolean
On Error Resume Next
NamedRangeExists = ThisWorkbook.Names(sName).Index <> (Err.Number = 0)
On Error GoTo 0
End Function
For the activeworkbook, you could also call the old XLM NAMES() function:
Function IsNameInActiveWorkbook(sName As String) As Boolean
IsNameInActiveWorkbook = Not IsError(Application.ExecuteExcel4Macro("MATCH(""" & sName & """,NAMES(),0)"))
End Function
As per Tom's answer these 2 line should do the trick:
On Error Resume Next
Set TestRange = ActiveWorkbook.Range("LoadedToken") 'if it does **not** exist this line will be ERROR

check if array is empty (vba excel)

These if ... then statements are getting the wrong results in my opinion. The first is returning the value 'false' when it should be 'true'. The fourth returns the right value. The second and third return an error.
Sub empty_array()
Dim arr1() As Variant
If IsEmpty(arr1) Then
MsgBox "hey"
End If
If IsError(UBound(arr1)) Then
MsgBox "hey"
End If
If IsError(Application.match("*", (arr1), 0)) Then
MsgBox "hey"
End If
ReDim arr1(1)
arr1(1) = "hey"
If IsEmpty(arr1) Then
MsgBox "hey"
End If
End Sub
Arr1 becomes an array of 'Variant' by the first statement of your code:
Dim arr1() As Variant
Array of size zero is not empty, as like an empty box exists in real world.
If you define a variable of 'Variant', that will be empty when it is created.
Following code will display "Empty".
Dim a as Variant
If IsEmpty(a) then
MsgBox("Empty")
Else
MsgBox("Not Empty")
End If
Adding into this: it depends on what your array is defined as. Consider:
dim a() as integer
dim b() as string
dim c() as variant
'these doesn't work
if isempty(a) then msgbox "integer arrays can be empty"
if isempty(b) then msgbox "string arrays can be empty"
'this is because isempty can only be tested on classes which have an .empty property
'this do work
if isempty(c) then msgbox "variants can be empty"
So, what can we do? In VBA, we can see if we can trigger an error and somehow handle it, for example
dim a() as integer
dim bEmpty as boolean
bempty=false
on error resume next
bempty=not isnumeric(ubound(a))
on error goto 0
But this is really clumsy... A nicer solution is to declare a boolean variable (a public or module level is best). When the array is first initialised, then set this variable.
Because it's a variable declared at the same time, if it loses it's value, then you know that you need to reinitialise your array.
However, if it is initialised, then all you're doing is checking the value of a boolean, which is low cost. It depends on whether being low cost matters, and if you're going to be needing to check it often.
option explicit
'declared at module level
dim a() as integer
dim aInitialised as boolean
sub DoSomethingWithA()
if not aInitialised then InitialiseA
'you can now proceed confident that a() is intialised
end sub
sub InitialiseA()
'insert code to do whatever is required to initialise A
'e.g.
redim a(10)
a(1)=123
'...
aInitialised=true
end sub
The last thing you can do is create a function; which in this case will need to be dependent on the clumsy on error method.
function isInitialised(byref a() as variant) as boolean
isInitialised=false
on error resume next
isinitialised=isnumeric(ubound(a))
end function
#jeminar has the best solution above.
I cleaned it up a bit though.
I recommend adding this to a FunctionsArray module
isInitialised=false is not needed because Booleans are false when created
On Error GoTo 0 wrap and indent code inside error blocks similar to with blocks for visibility. these methods should be avoided as much as possible but ... VBA ...
Function isInitialised(ByRef a() As Variant) As Boolean
On Error Resume Next
isInitialised = IsNumeric(UBound(a))
On Error GoTo 0
End Function
I would do this as
if isnumeric(ubound(a)) = False then msgbox "a is empty!"
I may be a bit late, but following simple stuff works with string arrays:
Dim files() As String
files = "..." 'assign array
If Not Not files Then
For i = LBound(files) To UBound(files)
'do stuff, array is not empty
Next
End If
That's all the code for this.
Above methods didn´t work for me. This did:
Dim arrayIsNothing As Boolean
On Error Resume Next
arrayIsNothing = IsNumeric(UBound(YOUR_ARRAY)) And False
If Err.Number <> 0 Then arrayIsNothing = True
Err.Clear
On Error GoTo 0
'Now you can test:
if arrayIsNothing then ...
this worked for me:
Private Function arrIsEmpty(arr as variant)
On Error Resume Next
arrIsEmpty = False
arrIsEmpty = IsNumeric(UBound(arr))
End Function
The problem with VBA is that there are both dynamic and static arrays...
Dynamic Array Example
Dim myDynamicArray() as Variant
Static Array Example
Dim myStaticArray(10) as Variant
Dim myOtherStaticArray(0 To 10) as Variant
Using error handling to check if the array is empty works for a Dynamic Array, but a static array is by definition not empty, there are entries in the array, even if all those entries are empty.
So for clarity's sake, I named my function "IsZeroLengthArray".
Public Function IsZeroLengthArray(ByRef subject() As Variant) As Boolean
'Tell VBA to proceed if there is an error to the next line.
On Error Resume Next
Dim UpperBound As Integer
Dim ErrorNumber As Long
Dim ErrorDescription As String
Dim ErrorSource As String
'If the array is empty this will throw an error because a zero-length
'array has no UpperBound (or LowerBound).
'This only works for dynamic arrays. If this was a static array there
'would be both an upper and lower bound.
UpperBound = UBound(subject)
'Store the Error Number and then clear the Error object
'because we want VBA to treat unintended errors normally
ErrorNumber = Err.Number
ErrorDescription = Err.Description
ErrorSource = Err.Source
Err.Clear
On Error GoTo 0
'Check the Error Object to see if we have a "subscript out of range" error.
'If we do (the number is 9) then we can assume that the array is zero-length.
If ErrorNumber = 9 Then
IsZeroLengthArray = True
'If the Error number is something else then 9 we want to raise
'that error again...
ElseIf ErrorNumber <> 0 Then
Err.Raise ErrorNumber, ErrorSource, ErrorDescription
'If the Error number is 0 then we have no error and can assume that the
'array is not of zero-length
ElseIf ErrorNumber = 0 Then
IsZeroLengthArray = False
End If
End Function
I hope that this helps others as it helped me.
I'm using this
If UBound(a) >= 0 Then
' not empty
Else
' empty... UBound(a) = -1
End If
IsEmpty(a) did not work for me... I hate VBA
Dim arr() As Variant
Debug.Print IsEmpty(arr) ' False
Debug.Print UBound(arr) ' raises error
arr = Array()
Debug.Print IsEmpty(arr) ' False
Debug.Print UBound(arr) ' -1
ReDim Preserve arr(UBound(arr) + 1)
arr(UBound(arr)) = "test"
Debug.Print IsEmpty(arr) ' False
Debug.Print UBound(arr) ' 0
The below function works for both static and dynamic arrays.
Function array_Empty(testArr As Variant) As Boolean
Dim i As Long, k As Long, flag As Long
On Error Resume Next
i = UBound(testArr)
If Err.Number = 0 Then
flag = 0
For k = LBound(testArr) To UBound(testArr)
If IsEmpty(testArr(k)) = False Then
flag = 1
array_Empty = False
Exit For
End If
Next k
If flag = 0 Then array_Empty = True
Else
array_Empty = True
End If
End Function
Tente isso:
Function inic(mtz As Variant) As Boolean
On Error Resume Next
Dim x As Boolean
x = UBound(mtz): inic = x
End Function
...
if inic(mymtz) then
debug.print "iniciada"
else
debug.print "não iniciada"
end if

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