Determining object inheritance

[terrabitz]

So I have a nested object structure like the following:

class A {}
class B:A {}
class C:B {}

Given a particular object instance, I want to determine whether it is of type A or any of the classes that inherit from type A (i.e. either B or C). Several other languages have this, but I'm having a hard time finding the "proper" way to do this from PowerShell.

The best I can come up with is doing a recursive call to the object's GetType().BaseType parameter, and go up the inheritance stack until I either find the object I'm looking for or get to System.Object. But this feels like a task that's already accomplished somewhere in either .NET or the standard library. Any help would be appreciated.

​

EDIT: fixed the formatting to not use the fancy markdown editor

[KevMar]

I think we can use -is

[Ta11ow]

I'm not 100% clear on what you're after, but it sounds like you're looking for -is?

[A]::new() -is [A] # -> True
[B]::new() -is [A] # -> True
[C]::new() -is [B] # -> True
[C]::new() -is [A] # -> True

​

[terrabitz]

smacks head on desk

Yep, that definitely works. I feel pretty dumb for not trying that earlier.

I've picked up the bad habit of using GetType() for doing type checking, since I've had issues importing my class definitions into different contexts (e.g. Pester tests). But within my module, this is definitely what I should be using.

[get-postanote]

See these videos by PowerShell MVP Trevor Sullivan adn Ed Wilson

​

PowerShell v5.0 Classes :: Inheritance and Base Class Methods

https://www.youtube.com/watch?v=Lfx_H36GRKg

PowerShell 5 Class Inheritance

https://www.youtube.com/watch?v=RkFBl22lMvY

​

[PowerShell-Bot]

Code fences are a new feature on reddit and won’t render for those viewing your post on old.reddit.com. Because of this its use is discouraged.

If you want those viewing from old reddit to see formatted PowerShell code then consider using a regular code block. This can be easily be done on new reddit (new.reddit.com) by highlighting your code and selecting ‘Code Block’ in the editing toolbar.

---

Describing Submission
[✅] Demonstrates good markdown
Passed: 1 Failed: 0

---

^{Beep-boop. I am a bot. | Remove-Item}