Intelligently handling attributes when fetching an xml text value from XML using PowerShell

Question

To fetch the value of an XML element in powershell, we can simply write out the path by treating the elemnts as if they were properties of a PowerShell object; i.e. $xml.RootElement.ChildElement.GrandChild.

However, if the element we're interested in has an attribute associated, to get the text value we need to drill down to the text node; i.e. $xml.RootElement.ChildElement.GrandChild.'#text'.

Sadly when the element doesn't have an attribute, we can't use the text node; i.e. in that scenarion, $xml.RootElement.ChildElement.GrandChild.'#text' does not work.

Clear-Host
$example = [xml](@"
<demo>
    <element attribute='1'>10</element>
    <element>20</element>
</demo>
"@)

"just the element"
$example.demo.element 
"element's text"
$example.demo.element.'#text'

I've written a nasty workaround for this, but suspect that's the wrong approach / that PowerShell has a more elegant way to resolve this issue.

My Nasty Workaround:

function Get-TextNode {
    [CmdletBinding()]
    param (
        [Parameter(ValueFromPipeline = $true)]
        $xmlElement
    )
    process {
        if($xmlElement.Attributes.Count -eq 0) {
            $xmlElement
        } else {
            $xmlElement.'#text'
        }
    }
}

$example.demo.element | Get-TextNode

ps. I noticed that adding `$xmlElement.GetType()` to my command shows that the type of the element changes according to whether or not any attributes are present; i.e. if they are it's an `XmlElement`, if there aren't, it's a `String`.. — JohnLBevan, Oct 03 '16 at 14:21

JohnLBevan · Accepted Answer · 2016-10-03T14:48:32.240

The SelectNodes function works around this issue:

i.e.

$example.SelectNodes('/demo/element').'#text'

or

$example.SelectNodes('/demo/element/text()').Value

work as expected.

It's also possible to update nodes in this way:

Clear-Host

$example = [xml](@"
<demo>
    <x>5</x>
    <element attribute='1'>10</element>
    <element>20</element>
</demo>
"@)

$example.OuterXml
#Result: <demo><x>5</x><element attribute="1">10</element><element>20</element></demo>

$example.SelectNodes('/demo/element/text()') | %{ 
    $_.value = $_.ParentNode.ParentNode.SelectSingleNode('./x/text()').Value  
}

$example.OuterXml
#Result: <demo><x>5</x><element attribute="1">5</element><element>5</element></demo>

Intelligently handling attributes when fetching an xml text value from XML using PowerShell

1 Answers1