SelectSingleNode with XPath and multiple namespaces

Question

I'm trying to select a node in PowerShell which exist more then once. I declared the namespaces and try to select with XPath without success. I only get back NULL.

I'm not sure what I did wrong but I can select all settings with

$selectedNode = $xml.SelectSingleNode("//ns:settings[@pass='oobeSystem']", $NSMGR)

but I want to reach component with the attribute @name="Microsoft-Windows-Shell-Setup". I tried different ways, but the result is always NULL.

Code snippet:

$NSMGR = New-Object System.Xml.XmlNamespaceManager($xml.NameTable)
#$NSMGR.AddNamespace("ns", $xml.DocumentElement.NamespaceURI) default
$NSMGR.AddNamespace("ns", "urn:schemas-microsoft-com:unattend")
$NSMGR.AddNamespace("xsi", "http://www.w3.org/2001/xmlSchema-instance") 

#first try
$selectedNode = $xml.SelectSingleNode("//ns:settings[@pass='oobeSystem']/component[@name='Microsoft-Windows-International-Core']", $NSMGR)
$selectedNode = $xml.SelectSingleNode("//ns:settings[@pass='oobeSystem']/xsi:component[@name='Microsoft-Windows-International-Core']", $NSMGR)
$selectedNode

#second try
$selectedNode = $xml.SelectSingleNode("//ns:settings[@pass='oobeSystem']", $NSMGR)
$selectedNode = $selectedNode.SelectSingleNode("//ns:component[@name='Microsoft-Windows-Shell-Setup']", $NSMGR) #Edit to MS Shell instead of internal core for my example
$selectedNode

XML snippet:

<?xml version="1.0" encoding="utf-8" ?>
<unattend xmlns="urn:schemas-microsoft-com:unattend" xmlns:wcm="http://schemas.microsoft.com/WMIConfig/2002/State" xmlns:ew="urn:schemas-microsoft-com:embedded.unattend.internal.v1">
  <settings pass="specialize">
    <component xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" name="Microsoft-Windows-Shell-Setup" processorArchitecture="amd64" publicKeyToken="31bf3856ad364e35" language="neutral" versionScope="nonSxS">
      <ComputerName>*</ComputerName>
      <TimeZone>UTC</TimeZone>
    </component>
    <component xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" name="Microsoft-Windows-International-Core" processorArchitecture="amd64" publicKeyToken="31bf3856ad364e35" language="neutral" versionScope="nonSxS">
      <InputLocale>0407:00000407</InputLocale>
      <UILanguage>en-US</UILanguage>
      <SystemLocale>en-US</SystemLocale>
      <UserLocale>en-US</UserLocale>
      <UILanguageFallback>de-DE</UILanguageFallback>
    </component>
  </settings>
  <settings pass="oobeSystem">
    <component xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" name="Microsoft-Windows-Shell-Setup" processorArchitecture="amd64" publicKeyToken="31bf3856ad364e35" language="neutral" versionScope="nonSxS">
      <OOBE>
        <ProtectYourPC>3</ProtectYourPC>
        <NetworkLocation>Work</NetworkLocation>
        <HideWirelessSetupInOOBE>true</HideWirelessSetupInOOBE>
      </OOBE>
    </component>
    <component xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" name="Microsoft-Windows-Embedded-Core-Settings" processorArchitecture="amd64" publicKeyToken="31bf3856ad364e35" language="neutral" versionScope="nonSxS">
      <HideEvaluationWarning>1</HideEvaluationWarning>
    </component>
  </settings>
  <settings pass="windowsPE">
    <component xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" name="Microsoft-Windows-International-Core-WinPE" processorArchitecture="amd64" publicKeyToken="31bf3856ad364e35" language="neutral" versionScope="nonSxS">
      <SetupUILanguage>
        <UILanguage>en-US</UILanguage>
        <WillShowUI>OnError</WillShowUI>
      </SetupUILanguage>
      <UserLocale>en-US</UserLocale>
      <UILanguage>en-US</UILanguage>
      <InputLocale>0407:00000407</InputLocale>
      <SystemLocale>en-US</SystemLocale>
    </component>
  </settings>
</unattend>

You create the namespace manager for namespaces from a variable $xmlNewUnattend, but select nodes from a variable $xml. Your second attempt worked fine for me when I created the namespace manager from $xml as well. — Ansgar Wiechers
– Ansgar Wiechers, Commented Feb 10, 2016 at 18:33
yes you are right, i just reduce the size and forgot to rename $xmlNewUnattend to $xml for my example. Ok in that syntax its right, but when you try to select "Microsoft-Windows-Shell-Setup" instead of internal core it will select the first node inside of the file but i want to catch the one under "oobeSystem". So my second try doesn't work properly — black
– black, Commented Feb 11, 2016 at 8:31

Ansgar Wiechers · Accepted Answer · 2016-02-11 08:57:39Z

1

Select the desired childnode relative to the particular parent node, like this:

$selectedNode = $xml.SelectSingleNode("//ns:settings[@pass='oobeSystem']/ns:component[@name='Microsoft-Windows-Shell-Setup']", $NSMGR)

or like this:

$parentNode = $xml.SelectSingleNode("//ns:settings[@pass='oobeSystem']", $NSMGR)
$selectedNode = $parentNode.SelectSingleNode("./ns:component[@name='Microsoft-Windows-Shell-Setup']", $NSMGR)

Note that you need to use the ns: namespace for both the parent and the child node.

answered Feb 11, 2016 at 8:57

Ansgar Wiechers

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3 Comments

black Over a year ago

It works..! :) i'm quiete sure that i try your way before but maybe there was an other issue at the moment so that this doesn't worked for me... Great thanks a lot :)

Ansgar Wiechers Over a year ago

@black Perhaps you used a wrong component name? Your "first try" example uses the component name Microsoft-Windows-International-Core, but there is no component with that name under the node <settings pass="oobeSystem">.

black Over a year ago

No, there is one in the full xmlfile. but i create it and use it afterwards. during creation it adds an attribute xlmns="" after that i was able to select this node without using the second ns:. But this only worked for nodes with xlmns="" (<component name="X" ... xlmns="">)in his tag. maybe this was the reason why i was confused about how it works. Now i delete all empty xlmns="" tags and use your solution and it works as it should :)

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