PowerShell $xml.NameTable is null

Question

I have an xml file that contains elements with namespaces that I am wishing to read using PowerShell.

Example XML:

    <ns0:Members xmlns:ns0="http://my.domain.com/subsite">
        <Member>
            <MemberDetails>
                <Name>Blah de Blah Blah</Name>
                <Email>blah@lost.com</Email>
            </MemberDetails>
        </Member>
    </Members>

From some examples I found online, I wrote the following PowerShell to read the XML:

   function Get-ScriptDirectory
    {
        return Split-Path $script:MyInvocation.MyCommand.Path
    }

    $xmlFile = Join-Path (Get-ScriptDirectory) "MyXmlFile.xml"
    [xml]$xmlDoc = Get-Content $xmlFile         
    $ns = new-object Xml.XmlNamespaceManager $xml.NameTable
    $ns.AddNamespace("ns0", "http://my.domain.com/subsite")
    $node = $xmlDoc.SelectNodes("ns0:Members")

However, I get the following error:

    New-Object : Constructor not found. Cannot find an appropriate constructor for type Xml.XmlNamespaceManager.

I searched online for the error but the only post I found suggested double-checking that the version of PowerShell was version 2.

I ran $Host.Version, which gave me:

    Major  Minor  Build  Revision
    -----  -----  -----  --------
    2      0      -1     -1

When I stepped through the script using PowerGui Editor, I discovered that $xml.NameTable is null.

Can anyone explain why and what I can do to fix it?

On another note, none of the methods I've tried to select the Members element has worked including Select-Xml and $xmlDoc.SelectNodes. The only way I could get it was using:

    $xmlDoc.Members

maybe I'm missing something here. In `$ns = new-object Xml.XmlNamespaceManager $xml.NameTable` you use the `$xml` variable, while your xmldoc is actually `$xmlDoc` — Frode F., Jan 09 '13 at 09:45
@Graimer That's what the example I found used - I wasn't sure if it should be $xmlDoc or whether $xml was something inbuilt — B-K, Jan 09 '13 at 21:57
@Graimer I tried changing it to $xmlDoc and that resolved the issue. Can you please provide your above response as an answer so I can mark it as the answer? Moral of the story - just because someone else says the code works doesn't mean they've actually provided you with working code ;) — B-K, Jan 09 '13 at 22:06
nothing built in, just normal to call the xml content for $xml :) — Frode F., Jan 09 '13 at 22:09

score 2 · Answer 1 · answered Jan 09 '13 at 04:58

2

Try using Select-Xml like so:

$ns = @{ns0='http://my.domain.com/subsite'}
$xml | Select-Xml -XPath '//ns0:Members' -Namespace $ns

answered Jan 09 '13 at 04:58

Keith Hill

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Thanks :) Your answer also worked for me once I changed $xml to $xmlDoc. – B-K Jan 09 '13 at 22:23

score 2 · Accepted Answer · answered Jan 09 '13 at 22:10

Try:

function Get-ScriptDirectory
    {
        return Split-Path $script:MyInvocation.MyCommand.Path
    }

    $xmlFile = Join-Path (Get-ScriptDirectory) "MyXmlFile.xml"
    [xml]$xmlDoc = Get-Content $xmlFile         
    $ns = new-object Xml.XmlNamespaceManager $xmlDoc.NameTable
    $ns.AddNamespace("ns0", "http://my.domain.com/subsite")
    $node = $xmlDoc.SelectNodes("ns0:Members")

Fixed typo.

PowerShell $xml.NameTable is null

2 Answers2

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