How to create new clone instance of PSObject object - powershell

Question

I want to create new instance of my custom PSObject. I have a Button object created as PSObject and I want to create new object Button2 which has the same members as Button does, but I can't find a way how to clone the original object without making it referenced in original object (if I change a property in Button2 it changes in Button as well). Is there a way how to do it similarly as with hashtables and arrays via some Clone() method?

Answer 1

Easiest way is to use the Copy Method of a PsObject ==> $o2 = $o1.PsObject.Copy()
$o1 = New-Object -TypeName PsObject -Property #{
Fld1 = 'Fld1';
Fld2 = 'Fld2';
Fld3 = 'Fld3'}
$o2 = $o1.PsObject.Copy()
$o2 | Add-Member -MemberType NoteProperty -Name Fld4 -Value 'Fld4'
$o2.Fld1 = 'Changed_Fld'
$o1 | Format-List
$o2 | Format-List
Output:
Fld3 : Fld3
Fld2 : Fld2
Fld1 : Fld1
Fld3 : Fld3
Fld2 : Fld2
Fld1 : Changed_Fld
Fld4 : Fld4

Answer 2

For some reason PSObject.Copy() doesn't work for all object types. Another solution to create a copy of an object is to convert it to/from Json then save it in a new variable:
$CustomObject1 = [pscustomobject]#{a=1; b=2; c=3; d=4}
$CustomObject2 = $CustomObject1 | ConvertTo-Json -depth 100 | ConvertFrom-Json
$CustomObject2 | add-Member -Name "e" -Value "5" -MemberType noteproperty
$CustomObject1 | Format-List
$CustomObject2 | Format-List

Answer 3

Indeed there is no clone method! However where there is a will...
$o = New-Object PsObject -Property #{ prop1='a' ; prop2='b' }
$o2 = New-Object PsObject
$o.psobject.properties | % {
$o2 | Add-Member -MemberType $_.MemberType -Name $_.Name -Value $_.Value
}
$o.prop1 = 'newvalue'
$o
$o2
Output:
prop2 prop1
----- -----
b newvalue
b a

Answer 4

Another possibility:
$o1 = New-Object PsObject -Property #{ prop1='a' ; prop2='b' }
$o2 = $o1 | select *
$o2.prop1 = 'newvalue'
$o1.prop1
$o2.prop1
a
newvalue

Answer 5

Here's a [pscustomobject] example with the hidden .psobject.copy():
$a = [pscustomobject]#{message='hi'}
$a.message
hi
$b = $a.psobject.copy()
$b.message
hi
$a.message = 'there'
$a.message
there
$b.message
hi

Answer 6

The Better way i found out was to use ConvertTo-Json and ConvertFrom-Json.
Ee -
Suppose you want to clone a object $toBeClonedObject, just run below code to clone.
$clonedObject = $toBeClonedObject | ConvertTo-Json | ConvertFrom-Json

Answer 7

Starting from PowerShell v5, you can use Class.
The problem with psobject.Copy() is, if you update the cloned object, then your template object's referenced properties will be also updated.
example:
function testTemplates
{
$PSCustomObjectTemplate = New-Object PSCustomObject -Property #{
List1 = [System.Collections.Generic.List[string]]#() # will be updated in template
String1 = "value1" # will not be updated in template
Bool1 = $false # will not be updated in template
}
$objectFromPSTemplate1 = $PSCustomObjectTemplate.psobject.Copy()
$objectFromPSTemplate1.List1.Add("Value")
$objectFromPSTemplate1.String1 = "value2"
$objectFromPSTemplate.Bool1 = $true
# $PSCustomObjectTemplate IS updated, so CANNOT be used as a clean template!
$PSCustomObjectTemplate
Class ClassTemplate {
[System.Collections.Generic.List[string]]$List1 = #() # will not be updated in template
[string]$String1 = "value1" # will not be updated in template
[bool]$Bool1 = $false # will not be updated in template
}
$objectFromClassTemplate = [ClassTemplate]::new()
$objectFromClassTemplate.List1.Add("Value")
$objectFromClassTemplate.String1 = "value2"
$objectFromClassTemplate.Bool1 = $true
# $ClassTemplate IS NOT updated, so can be used as a clean template!
[ClassTemplate]::new()
}
testTemplates
PS C:\Windows\system32> testTemplates
List1 String1 Bool1
----- ------- -----
{Value} value1 False
-> Template from PSCustomObject is updated (referenced property -List1)
List1 String1 Bool1
----- ------- -----
{} value1 False
-> Template from Class is safe

Answer 8

This usually works for me:
$Source = [PSCustomObject]#{ Value = 'Test' };
$Copy = ($Source | ConvertTo-Json) | ConvertFrom-Json;

Answer 9

Put this in a Utility class or define it in your current section
function clone($obj)
{
$newobj = New-Object PsObject
$obj.psobject.Properties | % {Add-Member -MemberType NoteProperty -InputObject $newobj -Name $_.Name -Value $_.Value}
return $newobj
}
Usage:
$clonedobj = clone $obj

Answer 10

Based on the answer by #TeraFlux, here's a function that will do a deep copy on multiple objects and accepts pipeline input.
Note, it leverages json conversion with a default depth of 100, which lends it to a few weaknesses
It's going to be slow on deep or complex objects, or objects with expensive (slow) pseudoproperties (methods pretending to be properties that are calculated on the fly when asked for)
Though it should still be faster than the Add-Member approach because the heavy lifting is going through a compiled function
Anything that can't be stored in JSON may get corrupted or left behind (methods will be a prime candidate for this type of error)
Though any object that can safely go through this process should be savable, able to be safely stored (for recovery) or exported for transportation
I would be interested in any caveats or improvements to deal with these
function Clone-Object {
[CmdletBinding()]
Param (
[Parameter(ValueFromPipeline)] [object[]]$objects,
[Parameter()] [int] $depth = 100
)
$clones = foreach( $object in $objects ){
$object `
| ConvertTo-Json `
-Compress `
-depth $depth `
| ConvertFrom-Json
}
return $clones
}
Here are some very basic unit tests
$testClone = {
$test1 = $null
$test2 = $null
$test3 = $null
$Test1 = [psCustomObject]#{a=1; b=2; c=3; d=4}
$Test2 = $Test1 | ConvertTo-Json -depth 100 | ConvertFrom-Json
$Test2 | add-Member -Name "e" -Value "5" -MemberType noteproperty
$Test3 = $test2 | Clone-Object
$Test3 | add-Member -Name "f" -Value "6" -MemberType noteproperty
$Test1.a = 7
$Test2.a = 8
#$Expected0 = [psCustomObject]#{a=1; b=2; c=3; d=4}
$Expected1 = [pscustomobject]#{a=7; b=2; c=3; d=4}
$Expected2 = [pscustomobject]#{a=8; b=2; c=3; d=4; e=5}
$Expected3 = [pscustomobject]#{a=1; b=2; c=3; d=4; e=5; f=6}
$results1 = #(); $results1+=$test1; $results1+=$expected1
$results2 = #(); $results2+=$test2; $results2+=$expected2
$results3 = #(); $results3+=$test3; $results3+=$expected3
$results1 | Format-Table # if these don't match then its probably passing references (copy not clone)
$results2 | Format-Table # if these don't match the core approach is incorrect
$results3 | Format-Table # if these don't match the function didn't work
}
&$testClone

Answer 11

Another option:
function Copy-Object($Object) {
$copy = #()
$Object.ForEach({
$currentObject = $_
$currentObjectCopy = New-Object $currentObject.GetType().Name
$currentObjectCopy.psobject.Properties.ForEach({
$_.Value = $currentObject.psobject.Properties[($_.Name)].Value
})
$copy += $currentObjectCopy
})
return $copy
}
Test objects:
class TestObjectA {
[string]$g
[int[]]$h
[string]getJ(){
return 'j'
}
}
class TestObjectB {
[string]$a
[int]$b
[hashtable]$c
[TestObjectA[]]$d
[string]getI(){
return 'i'
}
}
Tests:
$b = New-Object -TypeName TestObjectB -Property #{
a = 'value a'
b = 2
c = #{ e = 'value e'; f = 3 }
d = New-Object -TypeName TestObjectA -Property #{
g = 'value g'
h = #(4,5,6)
}
}
$bCopy = Copy-Object $b
# test with simple comparison
-not $(Compare-Object $b $bCopy)
True
# test json deep conversion output
$bJson = $b | ConvertTo-Json -Depth 10
$bCopyJson = $bCopy | ConvertTo-Json -Depth 10
-not $(Compare-Object $bJson $bCopyJson)
True
# test methods are intact
$bCopy.getI()
i
$bCopy.d.GetJ()
j
# test objects are seperate instances
$bCopy.b = 3
$b.b
2
$bCopy.b
3

Answer 12

Here's my version using Clixml
function Get-PSObjectClone {
param ( [psobject] $InputObject )
$_temp = New-TemporaryFile
$InputObject | Export-Clixml -Path $_temp -Depth 100
$_object = Import-Clixml -Path $_temp
Remove-Item $_temp -Force
Write-Output $_object
}
Works with everything I've thrown at it

Answer 13

Since Select-Object -Property expands wildcards in property names, a simple way to shallow-clone is this:
# Set up object
$o1 = [PSCustomObject]#{
Fld1 = 'Fld1';
Fld2 = 'Fld2';
Fld3 = 'Fld3'}
# Clone
$o2 = $o1 | Select-Object -Property *;
# Tests
$o1 -eq $o2;
$o1 | Format-List;
$o2 | Format-List;