PowerShell Classes and Class Lists

I found that I could use classes in PowerShell similar to how I use them in C#. I instantly wanted to play with this and I thought I would share this as well.

To create a class in PowerShell, it’s as simple as:

#Person class
class PersonClass{
	[String]$Name
	[Int]$Age
}

This allows a “Person” to be created that has the attributed of a name and an age. Simple stuff.

Say I wanted to have a bunch of these “Person”s in a list, a “People” list if you will. Then I could do something like this:

#Creating a list to hold the people using the PersonClass
$People = New-Object 'System.Collections.Generic.List[PSObject]'

#Creating a new person
$newPerson = [PersonClass]::new()
$newPerson.Name = "Roy Orbison"
$newPerson.Age = "24"

#Adding the new person to the people list
$People.Add($newPerson)

What if I wanted to add something like a “Pets” attribute onto the person? Well, I could create a new class to hold a framework for each pet and create a new list attribute in the PersonClass. Here is my PetClass:

#Pet class
class PetClass{
    [String]$Name
    [Int]$Age
    [String]$Color
}

And here is how I add it to my PersonClass so that I can have a list of pets for each user:

#Person class
class PersonClass{<br>    [String]$Name
    [Int]$Age
    [PetClass[]]$Pets
}

Now its really simple to create a list of people with a list of any pets that they might have. Stitching this all together, it looks like this:

#Person class
class PersonClass{
	[String]$Name
	[Int]$Age
    [PetClass[]]$Pets
}

#Pet class
class PetClass{
    [String]$Name
    [Int]$Age
    [String]$Color
}

#Creating a list to hold the people using the PersonClass
$People = New-Object 'System.Collections.Generic.List[PSObject]'

#Creating a new person
$newPerson = [PersonClass]::new()
$newPerson.Name = "Roy Orbison"
$newPerson.Age = "24"

#Adding pets to the new person
for ($i = 0; $i -le 5; $i++){
    $newPet = [PetClass]::new()
    $newPet.Name = $i
    $newPet.Age = $i + 2
    $newPet.Color = "Brown"

    #Adding the pet to the new person
    $newPerson.Pets += $newPet
}

#Adding the new person to the people list
$People.Add($newPerson)

Above you can see that I have created a new person called “Roy Orbison” with an age of “24” and I have added five pets. The pet names and age aren’t really accurate but it’s good enough for this demonstration.

Continuing from this, I could add as many users as I want or even create new classes to add extra framework information for existing classes.

Searching this information isn’t as straight forward in PowerShell as it is in C# but it’s still quite easy. You can see how I get a list of all the pets that Roy Orbison has below:

$People | Where-Object {$_.Name -eq "Roy Orbison"} | Select-Object -ExpandProperty Pets

Upon finishing this, I realised that it would have been much more appropriate to do the users and albums, instead of pets. But I’m far too lazy to change what I already have…

Enjoy!


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