PowerShell Property Sets →

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What are PowerShell Property sets and how can they be used?

Property sets are named groups of properties for certain types that can be used through Select-Object. The property sets are defined in the types.ps1xml files that can be found in the $pshome directory. Most of the types have default property sets defined as DefaultDisplayPropertertySet within the PSStandardMembers MemberSet. Those determine the list of properties shown when an object of that type is output. An example:

[code language=”powershell”] $process = (Get-Process)[0] $process.PSStandardMembers.DefaultDisplayPropertySet.ReferencedPropertyNames $process | Format-List [/code]

screenShotPropertySet1

The list of default properties for a type can be modified by using Update-TypeData:

[code language=”powershell”] $process = (Get-Process)[0] $typeName = $process.PSTypeNames[0] Update-TypeData -TypeName $typeName -DefaultDisplayPropertySet Handles, Name, ID -Force $process | Format-List [/code]

screenShotPropertySet

Some types have additional property sets defined that can be used with Select-Object:

[code language=”powershell”] Get-Process | select PSConfiguration -Last 5 | Format-Table -Auto [/code]

screenShotPropertySet2

The properties displayed when using the ‘PSConfiguration’ property set are defined in the types.ps1xml file but can be also accessed through Get-Member:

[code language=”powershell”] Get-Process | Get-Member -MemberType PropertySet [/code]

Property sets can also be added dynamically to any object instance by using Add-Member:

[code language=”powershell”] $ps = Get-Process $ps | Add-Member -MemberType PropertySet ‘Test’ (‘Path’, ‘Product’, ‘Company’, ‘StartTime’) $ps | select Test [/code]

Adding a property set to a type is unfortunately not as easy as just calling Update-TypeData, since the MemberType PropertySet is not supported:

[code language=”powershell”] $typeName = (Get-Process).GetType().FullName Update-TypeData -TypeName $typeName -MemberType PropertySet -MemberName ‘Test’ -Value $props Get-Process | select Test -First 5 [/code]

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That does of course not mean it’s impossible, but it involves creating the appropriate type.ps1xml file ‘manually’:

[code language=”powershell”] function Add-PropertySet{ <#
.SYNOPSIS Function to create property sets .DESCRIPTION Property sets are named groups of properties for certain types that can be used through Select-Object. The function adds a new property set to a type via a types.ps1xml file. .PARAM inputObject The object or collection of objects where the property set is added .PARAM propertySetName The name of the porperty set .EXAMPLE $fileName = dir | Add-PropertySet Testing (‘Name’, ‘LastWriteTime’, ‘CreationTime’) dir | Get-Member -MemberType PropertySet dir | select Testing #add this to the profile to have the property set available in all sessions Update-TypeData -PrependPath $fileName .EXAMPLE Get-Process | Add-PropertySet RAM (‘Name’, ‘PagedMemorySize’, ‘PeakWorkingSet’) Get-Process | select RAM #> [CmdletBinding()] param( [Parameter(ValueFromPipeline=$true,Mandatory=$true)] $inputObject,

    [Parameter(Mandatory=$true,Position=0)]
    $propertySetName,

    [Parameter(Mandatory=$true,Position=1)]
    $properties
)
$propertySetXML = "<Types>`n"
$groupTypes = $input | group { $_.PSTypeNames[0] } -AsHashTable
foreach ($entry in $groupTypes.GetEnumerator()) {
    $typeName = $entry.Key
    $propertySetXML += @"
<Type>
    <Name>$typeName</Name>
    <Members>
        <PropertySet>
            <Name>$propertySetName</Name>
            <ReferencedProperties>
                $($properties | foreach { 
                    "<Name>$_</Name>"    
                })
            </ReferencedProperties>
        </PropertySet>
    </Members>
</Type> "@
} 
$propertySetXML += "`n</Types>"
$xmlPath = Join-Path (Split-Path $profile.CurrentUserCurrentHost)  ($propertySetName + '.types.ps1xml')
([xml]$propertySetXML).Save($xmlPath)    
Update-TypeData -PrependPath $xmlPath
$xmlPath } [/code]

With Add-PropertySet property sets can also be easily added to types:

[code language=”powershell”] Get-Process | Add-PropertySet RAM (‘Name’, ‘PagedMemorySize’, ‘PeakWorkingSet’) Get-Process | select RAM -First 3 | Format-Table -Auto Get-Process | Get-Member -MemberType PropertySet [/code]

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The property set is by default only available for the current PowerShell session. In order to have the property set available for every session the Update-TypeData call with the return value from the Add-PropertySet function (the types.ps1xml are created within the same directory as the profile and prefixed with the propertySetName) needs to be added to the profile:

[code language=”powershell”] #add this to your profile Update-TypeData -PrependPath PATHRETURNEDFROMADD-PROPERTYSET [/code]

Add-PropertySet including full help can be download from my GitHub repository.

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photo credit: Happy Lazy Saturday via photopin (license)

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