Emulating a class with methods in a module

Question

I am using PowerShell 2.0 (can't upgrade) and I am writing a series of scripts that uses some information from Active Directory. Coming from an OOP languages like C++, I want to emulate a class in PowerShell 2.0, but I know that they only have the class statement in 5.0, and I don't want to use C# to embed classes because I already have a functions (which will be my methods) written in Powershell..

I read this: Powershell. Create a class file to hold Custom Objects?

And I am able to do a function creating a PSObject with "members", but not sure how to make it work with methods so that I can just load the function in my scripts to have a cleaner code.

This is what I have so far:

function New-User {

    param($user,
         $headers = @("header1","header2","header3","header4") )

    $new_user = New-Object -TypeName PSObject
    foreach ($header in $headers){
        $new_user | Add-Member -membertype NoteProperty -name $header -value $user.$header
    }
   $new_user | Add-Member -membertype NoteProperty -name "othermember" -value ""
   $new_user.PSObject.Typenames.Insert(0,"AD-User")

   # Add methods here! for example:
   $new_user | Add-Member -membertype METHOD -name "othermember" -value     MYDEFINED_FUNCTION($new_user.header1)


   return $new_user

}

How I can do this so that I just have this function loaded in my script?

Thanks!

If you _really_ wanted a class did you look at Add-Type in the marked answer for that question. Other than that you might have an easier time using a scriptmethod and make sure your function is sourced before your "class" is used. — Matt, Mar 11 '16 at 14:59
Hi, you only want to declare this once "somewhere", and make an "include" in your script ? — sodawillow, Mar 11 '16 at 14:59
Yes, I want to declare this as a "module" or just a file where I can load the emulatated class inside my scripts. For example, if the class filename is class.ps1, then that I can do something like $user = New-User(param1,param2,param3) — Edwardo, Mar 11 '16 at 15:03
@Matt Yes, but I dont want to embed C# code (can learn it quickly, but still need to rewrite the code to C#). Can you give me an example of using the script method? this should be on self-contain file, so that I can load it on my scripts. — Edwardo, Mar 11 '16 at 15:07

Matt · Answer 1 · 2016-03-11T15:41:40.190

ScriptMethods could fill the gap you are looking for here. Assuming the object has a property for firstname and lastname you could do something like this.

$new_user | Add-Member -membertype ScriptMethod -name samaccountname -value  {$this.firstname.substring(0,1) + $this.LastName}

Then with the returned object you can call the scriptmethod samaccountname

$matt = New-Object -TypeName psobject -Property @{
    firstname = "matt"
    lastname = "bagel"
}

$new = new-user $matt "firstname","lastname"
$new.samaccountname()

Which would return "mbagel". This was tested on 2.0.

So if you wanted to use a function in the method that is just a matter of making sure it is sourced ahead of the time it is called.

function Get-AccoutName{
    param(
        [string]$firstname,
        [string]$lastname
    )

    $firstname.substring(0,1) + $lastname
}
.....
other code you have
.....
$new_user | Add-Member -membertype ScriptMethod -name samaccountname -value  {Get-AccoutName $this.firstname $this.LastName}

If you want these things available all the time then you just need to load them into a PowerShell profile.

Emulating a class with methods in a module

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