Use of delegate declaration in Add-Type:d C# code causes methods to not be callable

Question

Adding a delegate to C# code in powershell seems to fail it, and my question is why and if there is any workarounds to get this working (other than using Func or Action)

Testcase:

$id = get-random
$tester = Add-Type -TypeDefinition @"
using System;

public static class Class$id {
    public static void test()
    {
        Console.WriteLine("test$id");
    }

    private delegate void doStuff(); // comment out this line and we are ok?
}
"@ -Language CSharp -PassThru
$tester
$tester::test()

Results in

PS C:\> $tester

IsPublic IsSerial Name                                     BaseType
-------- -------- ----                                     --------
True     False    Class897305760                           System.Object
False    True     doStuff                                  System.MulticastDelegate


PS C:\> $tester::test()
Method invocation failed because [System.Object[]] does not contain a method named 'test'.
At line:1 char:1
+ $tester::test()
+ ~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidOperation: (:) [], RuntimeException
    + FullyQualifiedErrorId : MethodNotFound

Removing or commenting out private delegate void doStuff(); instead runs ok:

PS C:\> $tester

IsPublic IsSerial Name                                     BaseType
-------- -------- ----                                     --------
True     False    Class883741893                           System.Object


PS C:\> $tester::test()
test883741893

Here we can see that doStuff is available outside the class, not sure if that is relevant in some way.

I do intend to use the delegate, but that part of the code is not needed to reproduce the issue, so left it out. My current workaround is to use Action<> instead, but in this case it reduces self documentation which I would like to have if at all possible.

Mathias R. Jessen · Accepted Answer · 2020-11-26 12:07:13Z

2

Add-Type returns both the Class$ID type as well as the delegate type - so $tester is an array containing both:

$class = $tester |Where Name -like 'Class*' |Select -First 1
$class::test() # this should work now, with or without the delegate

answered Nov 26, 2020 at 12:07

Mathias R. Jessen

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3 Comments

NiKiZe Over a year ago

The only thing left to have explained is why the delegate is included in this unexpected way. (why not functions, enums or other parts)

Mathias R. Jessen Over a year ago

@NiKiZe It's not unexpected - Add-Type -PassThru returns all types - including classes, enums, delegates. Try Add-Type 'public enum A{} public enum B{}'

NiKiZe Over a year ago

The lovely inner structures of MSIL i guess? The unexpected (inconsistency) for me is that we get one class, and then a delegate, even if that delegate is in the class. since the delegate is there on the same level as the class, I would have expect the methods to be on the same level as well.

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