Access VBA XML Code not Working with MSXML 6

[RMittelman]

I recently upgraded my development PC and some of the XML functionality stopped working properly. I was using MSXML2 on the old PC. That wasn't available on the new PC, just MSXML3 and MSXML6, so I decided to move to the version 6. Here is a snippet of some code from an XML class I wrote:

Dim xDoc    As MSXML2.DOMDocument60
Dim root    As MSXML2.IXMLDOMNode
Dim m_node  As MSXML2.IXMLDOMNode

Public Function LoadXmlFile(fileName As String) As Boolean

    LoadXmlFile = False
    
    On Error Resume Next
    Set xDoc = New DOMDocument60 ' MSXML2.DOMDocument
    If Err.Number = 0 Then
        xDoc.async = False
        xDoc.validateOnParse = False
        xDoc.Load (fileName)
        If Err.Number <> 0 Then
            m_error = Err.Description
            Set xDoc = Nothing
            Set root = Nothing
        Else
            m_error = ""
            Set root = xDoc.DocumentElement
            LoadXmlFile = True
        End If
    End If
    On Error GoTo 0

End Function

Public Function GetNodeByName(Name As String) As Boolean

    GetNodeByName = False
    If Not xDoc Is Nothing Then
        On Error Resume Next
        Set m_node = xDoc.SelectSingleNode("//" & Name)
        GetNodeByName = Not m_node Is Nothing
        m_error = IIf(Err.Number = 0, "", Err.Description)
        On Error GoTo 0
    End If

End Function

Here is some of my calling code:

    Const xml_file  As String = "C:\ProgramData\EDESuite\Year{year}\EDExpress for Windows\EDESuite.xml"

    Dim oXml        As New clsXML
    Dim fso         As New FileSystemObject
    Dim valName     As String
    Dim xmlFile     As String
    Dim isOK        As Boolean
    
    valName = ""
    xmlFile = Replace$(xml_file, "{year}", awdYear)
    isOK = fso.FileExists(xmlFile)
    If isOK Then
        isOK = oXml.LoadXmlFile(xmlFile)
        If isOK Then isOK = oXml.GetNodeByName("Database")
        If isOK Then
            valName = oXml.GetNodeAttributeValue("Path")
            isOK = valName <> "~"
        End If
    Else
        MsgBox "EDESuite.xml file not found." & vbCrLf & "Please contact Tech Support", vbExclamation, "Error"
    End If

So this statement: isOK = oXml.LoadXmlFile(xmlFile)
works, and the XML file loads fine. Here is the xml from the file after executing the above statement

<?xml version="1.0"?><EDESuite xmlns="http://tempuri.org/EDESuiteAppSettings.xsd">
    <Database Path="M:\FedConnect\Schools\UAV\Expres19.accdb"></Database>
    <Executable Path="C:\Program Files (x86)\EDESuite\EDExpress for Windows 2018-2019"></Executable>
    <InstalledModules>
        <Module Name="ApplicationProcessing" Load="true"></Module>
        <Module Load="false" Name="COD"></Module>
        <Module Load="false" Name="DirectLoan"></Module>
        <Module Name="FinancialAidShoppingSheet" Load="true"></Module>
        <Module Name="Global" Load="true"></Module>
        <Module Name="Packaging" Load="true"></Module>
        <Module Load="false" Name="Pell"></Module>
        <Module Load="false" Name="TEACH"></Module>
    </InstalledModules>
</EDESuite>

The problem occurs with the statement: If isOK Then isOK = oXml.GetNodeByName("Database")
When I step through the GetNodeByName method, the statement: Set m_node = xDoc.SelectSingleNode("//" & Name)
returns Nothing for m_node.

This has always worked in he past, but now it doesn't. The x-path seems to be right. Is there some difference with MSXML6 that I am missing?

Thanks...

[RMittelman]

I noticed that if I switch the reference to MSXML3 it seems to work again. I'd still like to know why the same code works on MSXML3 but not MSXML6...

[RMittelman]

I seem to have found the solution. According to this article: https://docs.microsoft.com/en-us/pre...des-not-return,
MSXML6 has a higher level of security, and if the XML file has a default namespace you need to tell the document object about it by adding a namespace prefix.

This code seems to work now:

Dim m_hasNamespace As Boolean

Public Function LoadXmlFile(fileName As String) As Boolean

    Dim isOK    As Boolean
    
    LoadXmlFile = False
    
    On Error Resume Next
    Set xDoc = New MSXML2.DOMDocument60


    If Err.Number = 0 Then
        
        xDoc.async = False
        xDoc.validateOnParse = False
        xDoc.Load (fileName)
        If Err.Number <> 0 Then
            
            m_error = Err.Description
            Set xDoc = Nothing
            Set root = Nothing
            
        Else
            
            If FixNamespace Then
                m_error = ""
                Set root = xDoc.DocumentElement
                LoadXmlFile = True
            Else
                m_error = "Couldn't add namespace prefix"
            End If

        End If
    End If
    On Error GoTo 0


End Function

Private Function FixNamespace() As Boolean

    FixNamespace = False
    On Error Resume Next
    m_hasNamespace = Nz(xDoc.namespaces(0), "") > ""
    If m_hasNamespace Then
        xDoc.SetProperty "SelectionNamespaces", "xmlns:doc='" & xDoc.namespaces(0) & "'"
    End If
    FixNamespace = Err.Number = 0

End Function

Then I modified the code the GetNodeByName function as follows:

Public Function GetNodeByName(Name As String) As Boolean

    GetNodeByName = False
    If Not xDoc Is Nothing Then
        On Error Resume Next
        Set m_node = xDoc.SelectSingleNode("//" & IIf(m_hasNamespace, "doc:", "") & Name)
        GetNodeByName = Not m_node Is Nothing
        m_error = IIf(Err.Number = 0, "", Err.Description)
        On Error GoTo 0
    End If


End Function

Not sure how to adapt this for an XML file with multiple default namespaces, but for now it seems to work fine.