Getting the range used to define error bars with VBA - excel

Question

I have an Excel chart. One of the series has X and Y error bars, defined from worksheet ranges.
I want to get via VBA those ranges (not set them). Is this possible?

Answer 1

Jon Peltier has an article about error bars on his blog here
Quoting from that:
Programmatically Defining Custom Error Bars
The command to add error bars using Excel is: {Series}.ErrorBar
Direction:={xlX or xlY}, Include:=xlBoth, Type:=xlCustom, _
Amount:={positive values}, MinusValues:={negative values} Values can be a single numerical value, for example, 1, an comma-separated
array of numerical values in curly braces, such as {1,2,3,4}, or a
range address in R1C1 notation. For values in Sheet1!$G$2:$G$10, enter
the address as Sheet1!R2C7:R10C7. Combine both plus and minus in the
same command. In Excel 2007, if you don’t want to show a particular
error bar, you must enter a value of zero in this command. In 2003,
you can enter a null string “”. In Excel 2003, the range address must
begin with an equals sign, =Sheet1!R2C7:R10C7; Excel 2007 accepts the
address with or without the equals sign. Single values or arrays may
be entered with or without the equals sign in either version of Excel.
In a post on Ozgrid, Jon Peltier says
the range for custom error bar values is not exposed to VBA
If Jon says it can't be done, it can't be done.

Answer 2

I know I'm 8 years late to the party here... but I stumbled upon this while scouring the web for the answer to this same question. I came up empty too, so I decided to devise my own solution, and figured I might as well post it on the off chance that someone else ends up here.
It works by extracting the workbook XML to a temporary folder, locating the error bar reference in the XML, and returning it as a Range object. You therefore have to save changes to the workbook before the function will work. If you change the error bar range without saving, the function will still return the old range from the most recent save. It also will not work on files from Excel 2003 or earlier (.xls).
It's anything but elegant... but at least this is technically possible!
To use: just copy the code below into a standard module, and call GetErrorBarRange(MySeries.ErrorBars, enErrorBarPlus) for the source range of the positive error bar, or GetErrorBarRange(MySeries.ErrorBars, enErrorBarMinus) for the source range of the negative error bar (where MySeries.ErrorBars is some ErrorBars object). Passing the optional third argument AutoSave:=True will save the containing workbook automatically before looking for the error bar source ranges.
' Created by Ryan T. Miller in 2022
' You may use this code in your own work however you wish. It'd be real swell of you
' to leave this credit in if you do, but I'm not gonna force you to.
Option Explicit
Option Private Module
Public Enum EnErrorBarPlusMinus
enErrorBarPlus
enErrorBarMinus
End Enum
Private moFSO As Object
' Get error bar source range from ErrorBars object
Public Function GetErrorBarRange(oErrorBars As ErrorBars, _
PlusMinus As EnErrorBarPlusMinus, _
Optional AutoSave As Boolean) As Range
Dim oFile As Object
Dim strTempDir As String
Dim strSubfolder As String
Dim oSeries As Series
Dim oChart As Chart
Dim oSheet As Object
Dim oWb As Workbook
Dim strPrefix As String
Dim strSeriesName As String
Dim strChartName As String
Dim strSheetName As String
Dim strXMLFile As String
Dim strXPath As String
Dim strCurrentSheet As String
Dim strRelId As String
Dim strDrawingXml As String
Dim strChartXml As String
Dim strErrValType As String
Dim strErrBarType As String
Dim strErrBarFormula As String
Dim rngResult As Range
On Error GoTo CleanUp
If Not (PlusMinus = enErrorBarMinus _
Or PlusMinus = enErrorBarPlus) Then Exit Function
Set moFSO = CreateObject("Scripting.FileSystemObject")
Application.Cursor = xlWait
' Set Series, Chart, Sheet, and Workbook objects
Set oSeries = oErrorBars.Parent
Set oChart = oSeries.Parent.Parent
If TypeOf oChart.Parent Is ChartObject Then
' Chart is on a worksheet
Set oSheet = oChart.Parent.Parent
strPrefix = "work"
Else
' Chart is on its own chart sheet
Set oSheet = oChart
strPrefix = "chart"
End If
Set oWb = oSheet.Parent
If AutoSave Then oWb.Save
' Name of the series, chart & its parent sheet
strSeriesName = oSeries.Name
strChartName = oChart.Parent.Name
strSheetName = oSheet.CodeName
strTempDir = ExtractWorkbookXMLToTemp(oWb)
' Loop over worksheet/chartsheet XML files & find the one where /worksheet/sheetPr/#codeName=strSheetName
' Then get strRelId from /worksheet/drawing/#r:id
' This is the ID which specifies which relationship links the sheet to the drawings.
strSubfolder = moFSO.BuildPath(strTempDir, "xl\" & strPrefix & "sheets")
strXPath = "/x:" & strPrefix & "sheet/x:sheetPr/#codeName"
For Each oFile In moFSO.GetFolder(strSubfolder).Files
strXMLFile = moFSO.BuildPath(strSubfolder, oFile.Name)
strCurrentSheet = GetXPathFromXMLFile(strXMLFile, strXPath)
If strSheetName = strCurrentSheet Then Exit For
Next oFile
strXPath = "/x:" & strPrefix & "sheet/x:drawing/#r:id"
strRelId = GetXPathFromXMLFile(strXMLFile, strXPath)
' Open the _rels XML associated with the correct sheet.
' Then get strDrawingXml from /Relationships/Relationship[#Id='strRelId']/#Target
' This is the name of the drawing XML.
strSubfolder = strSubfolder & "\_rels"
strXMLFile = moFSO.BuildPath(strSubfolder, moFSO.GetFileName(strXMLFile)) & ".rels"
strXPath = "/rel:Relationships/rel:Relationship[#Id='" & strRelId & "']/#Target"
strDrawingXml = GetXPathFromXMLFile(strXMLFile, strXPath)
strDrawingXml = Replace$(Replace$(strDrawingXml, "../", "/"), "/", "\")
' Open the correct drawing XML file (strDrawingXml)
' Then get strRelId from xdr:wsDr//xdr:graphicFrame[xdr:nvGraphicFramePr/xdr:cNvPr/#name='strChartName']/a:graphic/a:graphicData/c:chart/#r:id
' Or, if oSheet is a ChartSheet, there will only be 1 chart, so just get xdr:wsDr//xdr:graphicFrame/a:graphicData/a:graphic/c:chart/#r:id
' This is the ID which specifies which relationship links the drawing to the chart.
strXMLFile = moFSO.BuildPath(strTempDir, "xl" & strDrawingXml)
strXPath = "xdr:wsDr//xdr:graphicFrame" & _
IIf(TypeOf oChart.Parent Is ChartObject, "[xdr:nvGraphicFramePr/xdr:cNvPr/#name='" & strChartName & "']", vbNullString) & _
"/a:graphic/a:graphicData/c:chart/#r:id"
strRelId = GetXPathFromXMLFile(strXMLFile, strXPath)
' Open the _rels associated with the correct drawing XML.
' Then get strChartXml = /Relationships/Relationship[#Id='strRelId']/#Target
' This is the name of the chart XML.
strSubfolder = moFSO.GetParentFolderName(strXMLFile) & "\_rels"
strXMLFile = moFSO.BuildPath(strSubfolder, moFSO.GetFileName(strXMLFile)) & ".rels"
strXPath = "/rel:Relationships/rel:Relationship[#Id='" & strRelId & "']/#Target"
strChartXml = GetXPathFromXMLFile(strXMLFile, strXPath)
strChartXml = Replace$(Replace$(strChartXml, "../", "/"), "/", "\")
' Open the correct chart XML file (strChartXml)
strXMLFile = moFSO.BuildPath(strTempDir, "xl" & strChartXml)
' Get error bar value type. If the error bar is set to a Range then this must be 'cust'.
strXPath = "/c:chartSpace/c:chart//c:ser[c:tx//c:v[text()='" & strSeriesName & "']]/c:errBars/c:errValType/#val"
strErrValType = GetXPathFromXMLFile(strXMLFile, strXPath)
' Get error bar type. This can be "minus", "plus", or "both" depending on which error bar(s) exist(s).
strXPath = "/c:chartSpace/c:chart//c:ser[c:tx//c:v[text()='" & strSeriesName & "']]/c:errBars/c:errBarType/#val"
strErrBarType = GetXPathFromXMLFile(strXMLFile, strXPath)
' Get the Range address for either the "minus" or "plus" error bar and set it to the final result.
If strErrValType = "cust" Then
strXPath = "/c:chartSpace/c:chart//c:ser[c:tx//c:v[text()='" & strSeriesName & "']]/c:errBars"
If PlusMinus = enErrorBarMinus And (strErrBarType = "both" Or strErrBarType = "minus") Then
strXPath = strXPath & "/c:minus/c:numRef/c:f"
ElseIf PlusMinus = enErrorBarPlus And (strErrBarType = "both" Or strErrBarType = "plus") Then
strXPath = strXPath & "/c:plus/c:numRef/c:f"
EndIf
strErrBarFormula = GetXPathFromXMLFile(strXMLFile, strXPath)
strErrBarFormula = "'[" & oWb.Name & "]" & Replace$(strErrBarFormula, "!", "'!")
Set rngResult = Application.Range(strErrBarFormula)
End If
Set GetErrorBarRange = rngResult
CleanUp:
' Delete the temporary extracted XML data
With moFSO
If .FolderExists(strTempDir) Then .DeleteFolder strTempDir
End With
Set moFSO = Nothing
' Free the cursor
Application.Cursor = xlDefault
End Function
' Get the value of an XML node by an XPath search string
Private Function GetXPathFromXMLFile(ByVal strXMLFile As String, ByVal strXPath As String) As String
Dim objXMLDoc As Object
Dim strNS As String
Dim objXMLNode As Object
' Load the XML file
Set objXMLDoc = CreateObject("MSXML2.DOMDocument.6.0")
objXMLDoc.Load strXMLFile
' These are all the XML namespaces related to the current task
strNS = Join$(Array( _
"xmlns:x=""http://schemas.openxmlformats.org/spreadsheetml/2006/main""", _
"xmlns:r=""http://schemas.openxmlformats.org/officeDocument/2006/relationships""", _
"xmlns:mc=""http://schemas.openxmlformats.org/markup-compatibility/2006""", _
"xmlns:x14ac=""http://schemas.microsoft.com/office/spreadsheetml/2009/9/ac""", _
"xmlns:xr=""http://schemas.microsoft.com/office/spreadsheetml/2014/revision""", _
"xmlns:xr2=""http://schemas.microsoft.com/office/spreadsheetml/2015/revision2""", _
"xmlns:xr3=""http://schemas.microsoft.com/office/spreadsheetml/2016/revision3""", _
"xmlns:rel=""http://schemas.openxmlformats.org/package/2006/relationships""", _
"xmlns:xdr=""http://schemas.openxmlformats.org/drawingml/2006/spreadsheetDrawing""", _
"xmlns:a=""http://schemas.openxmlformats.org/drawingml/2006/main""", _
"xmlns:c=""http://schemas.openxmlformats.org/drawingml/2006/chart""", _
"xmlns:c16r2=""http://schemas.microsoft.com/office/drawing/2015/06/chart""" _
))
objXMLDoc.SetProperty "SelectionLanguage", "XPath"
objXMLDoc.SetProperty "SelectionNamespaces", strNS
objXMLDoc.resolveExternals = True
' Select the XML node and return its text value
Set objXMLNode = objXMLDoc.SelectSingleNode(strXPath)
If Not objXMLNode Is Nothing Then
GetXPathFromXMLFile = objXMLNode.Text
End If
End Function
' If workbook path is a OneDrive URL or a network share URL then resolve it to a local path with a drive letter
Private Function LocalFilePath(ByVal strFilePath As String)
strFilePath = OneDriveLocalFilePath(strFilePath)
strFilePath = NetworkLocalFilePath(strFilePath)
LocalFilePath = strFilePath
End Function
' If workbook path is a OneDrive URL then resolve it to a local path with a drive letter
Private Function OneDriveLocalFilePath(ByVal strFilePath As String) As String
Dim strOneDrivePath As String
Dim strLocalPath As String
If strFilePath Like "*my.sharepoint.com*" Then
strOneDrivePath = Environ$("OneDriveCommercial")
If strOneDrivePath = vbNullString Then strOneDrivePath = Environ$("OneDrive")
strLocalPath = strOneDrivePath & "/" & Split(strFilePath, "/", 7)(6)
OneDriveLocalFilePath = Replace$(strLocalPath, "/", "\")
ElseIf strFilePath Like "*d.docs.live.net*" Then
strOneDrivePath = Environ$("OneDriveConsumer")
If strOneDrivePath = vbNullString Then strOneDrivePath = Environ$("OneDrive")
strLocalPath = strOneDrivePath & "/" & Split(strFilePath, "/", 5)(4)
OneDriveLocalFilePath = Replace$(strLocalPath, "/", "\")
Else
OneDriveLocalFilePath = strFilePath
End If
End Function
' If workbook path is a network share URL then resolve it to a local path with a drive letter
Private Function NetworkLocalFilePath(ByVal strFilename As String) As String
On Error Resume Next
Dim ShellScript As Object
Dim i As Long
Dim strDriveLetter As String * 1
Dim strRemotePath As String
Set ShellScript = CreateObject("WScript.Shell")
For i = 97 To 122 ' a to z
strDriveLetter = Chr$(i)
strRemotePath = ShellScript.RegRead("HKEY_CURRENT_USER\Network\" & strDriveLetter & "\RemotePath")
If Err.Number = 0 Then
If strFilename Like strRemotePath & "*" Then
NetworkLocalFilePath = Replace$(strFilename, strRemotePath, UCase$(strDriveLetter) & ":", Count:=1)
Exit Function
End If
Else
Err.Clear
End If
Next i
NetworkLocalFilePath = strFilename
End Function
' Extract workbook XML to temporary directory
Private Function ExtractWorkbookXMLToTemp(oWb As Workbook) As String
Dim strTempDir As String
Dim strExt As String
Dim strTempWb As String
Dim strWbLocal As String
Dim strZipFile As String
On Error GoTo CleanUp
' Create a temporary copy of the workbook
With moFSO
strTempDir = .BuildPath(Environ$("TEMP"), _
Replace$(.GetTempName, ".tmp", vbNullString))
strExt = .GetExtensionName(oWb.Name)
strTempWb = strTempDir & "." & strExt
strWbLocal = LocalFilePath(oWb.FullName)
.CopyFile strWbLocal, strTempWb
End With
' Rename the temporary copy from .xls_ to .zip
strZipFile = strTempDir & ".zip"
Name strTempWb As strZipFile
' Unzip the .zip file to a temporary folder
MkDir strTempDir
UnzipFiles strZipFile, strTempDir
' Return the name of the temporary directory
ExtractWorkbookXMLToTemp = strTempDir
CleanUp:
' Delete the temporary ZIP file
With moFSO
If .FileExists(strZipFile) Then .DeleteFile strZipFile
End With
End Function
' Unzip all the files in 'varZipFile' into the folder 'varDestDir'
Private Sub UnzipFiles(ByVal varZipFile As Variant, ByVal varDestDir As Variant)
Dim oShellApp As Object
Const NO_PROGRESS_DIALOG As Integer = &H4
Set oShellApp = CreateObject("Shell.Application")
If Not varDestDir Like "*\" Then varDestDir = varDestDir & "\"
With oShellApp
.Namespace(varDestDir).CopyHere .Namespace(varZipFile).Items, NO_PROGRESS_DIALOG
End With
On Error Resume Next
With oShellApp
Do Until .Namespace(varZipFile).Items.Count = .Namespace(varDestDir).Items.Count
Application.Wait Date + (VBA.Timer + 1!) / 86400
Loop
End With
On Error GoTo 0
End Sub