can't parse Component Content XML via XPath

Question

I am using the PowerShell module to fetch a component via core service. My end goal is to update it and save it. however, I am failing to get started on the XML parsing aspect of things. So, this part is easy

$tridionItem = Get-TridionItem -Id "/webdav/C020%20Shared%20Global%20Content%20US%20English/Building%20Blocks/System/Content/Administration/Workflow/Workflow%20Configuration.xml"
$tridionItemContentXML = $tridionItem.Content
$xdoc = ConvertTo-Xml -InputObject $tridionItemContentXML

I exported the item XML to a file (shown below). So, then I tried both of these approaches. According to my XML tool, the XPath is valid. however... it may indeed be lying.

$test1 = Select-Xml -XPath "/*[local-name()='system_values']" -Xml $xdoc
$test1 = $xdoc.SelectNodes('/*[local-name()="system_values"]')

Both return null. So, I tried messing around with XMLNS but that hasn't changed things.

$ns = @{sv="http://www.mycompany.com/tridion/schema/system_values"}
$test1 = Select-Xml -XPath '/sv:system_values' -Xml $xdoc -Namespace $ns

Here's the item XML.

<system_values xmlns="http://www.mycompany.com/tridion/schema/system_values"><system_values><name>EmailFolder</name><value>/webdav/C020%20Shared%20Global%20Content%20US%20English/Building%20Blocks/System/Content/Administration/Workflow/Email</value></system_values><system_values><name>SMTPServer</name><value>server.mycompany.com</value></system_values><system_values><name>SMTPPort</name><value>25</value></system_values><system_values><name>SMTPUser</name></system_values><system_values><name>SMTPPassword</name></system_values><system_values><name>SMTPSSLEnabled</name><value>false</value></system_values><system_values><name>SMTPIsBodyHTML</name><value>true</value></system_values><system_values><name>EmailFrom</name><value>Tridion Workflow Agent &lt;sdl.deployer@mycompany.com&gt;</value></system_values><system_values><name>ContentManagerURL</name><value>https://server.mycompany.com:12301</value></system_values><system_values><name>CoreServiceEndPoint</name><value>net.tcp://localhost:2660/CoreService/netTcp_2010</value></system_values><system_values><name>PublishValidationTimedOutHours</name><value>72</value></system_values><system_values><name>EmailSwitch</name><value>ON</value></system_values></system_values>

Answer 1

I don't recognise Convert-To-Xml as a standard Powershell function, although maybe it's in a module you are using. In any case, to get the content into an XML document all you need to do is:

$xDoc = [xml]$tridionItem.Content

If Convert-To-Xml isn't working, Select-Xml will silently return null - you can test this simply like this:

PS C:\Users\Administrator> (select-xml -XPath "/*" -xml ([xml]"")) -eq $null
True