Adding properties to objects in PowerShell

Introduction

Adding properties to objects lets you store extra information in them. This helps you keep related data together in one place.

You want to add a new detail to an existing object without creating a new one.

You need to store extra information temporarily during a script.

You want to customize objects for reports or output with more fields.

You want to add notes or tags to objects for filtering later.

Syntax

PowerShell

$object | Add-Member -MemberType NoteProperty -Name PropertyName -Value PropertyValue

Use Add-Member to add a new property to an existing object.

NoteProperty is a simple property that holds a value.

Examples

Creates a new object and adds an Age property with value 30.

PowerShell

$person = New-Object PSObject
$person | Add-Member -MemberType NoteProperty -Name Age -Value 30
$person

Adds a Year property to an existing car object.

PowerShell

$car = [PSCustomObject]@{Make='Toyota'; Model='Camry'}
$car | Add-Member -MemberType NoteProperty -Name Year -Value 2020
$car

Adds a Color property and then accesses it.

PowerShell

$obj = New-Object PSObject
$obj | Add-Member -MemberType NoteProperty -Name Color -Value 'Blue'
$obj.Color

Sample Program

This script creates a book object and adds Title, Author, and Pages properties. Then it prints each property.

PowerShell

$book = New-Object PSObject
$book | Add-Member -MemberType NoteProperty -Name Title -Value 'The PowerShell Guide'
$book | Add-Member -MemberType NoteProperty -Name Author -Value 'Jane Doe'
$book | Add-Member -MemberType NoteProperty -Name Pages -Value 250
Write-Output "Title: $($book.Title)"
Write-Output "Author: $($book.Author)"
Write-Output "Pages: $($book.Pages)"

Important Notes

You can add multiple properties one by one using Add-Member.

Once added, you can access the new properties like normal object properties.

If you add a property that already exists, it will not overwrite it unless you use -Force.

Summary

Add-Member lets you add new properties to existing objects.

Use NoteProperty to add simple data fields.

Access added properties with dot notation like $object.PropertyName.