RGiesecke.DllExport.Metadata not found when trying to import DLL

[josemariagarcia95]

Hello! I posted this situation I have as an issue because I thought it was, but I was told to move it here, so I'll keep the format.

The main idea is that I'm trying to load a class in a DLL file using Python. This class (and most of its methods) is static (which at this point I think is related to my problem), and when I load it, the static methods are not there (although I can see them if I import that DLL in Visual Studio in a .NET project). The script I'm using is supposed to work under Pythonnet 2.3.0, but I couldn't install it, so I'm trying to make it work with the current versions of Python and Pythonnet I'm using.

Environment

• Pythonnet version: 3.0.2
• Python version: 3.11.5
• Operating System: Windows 11
• .NET Runtime: 4.8.09032

Details
I'm trying to import a DLL I was given by my company to use its functions in Python. I was also given a basic script to import said DLL and access its functions:

import clr
clr.AddReference(R'C:\Users\XXXXX\Documents\XXXXX\XXXXX.dll')
from OwnedPackage.Compression import QuickLZ

QuickLZ.compression() # This line returns an AttributeError, because QuickLZ doesn't have a compression method

However, after inspecting QuickLZ with dir, I discover that the imported object only contains "default" functions such as Equals, GetType, etc.

dir(QuickLZ)
['Equals',
 'Finalize',
 'GetHashCode',
 'GetType',
 'MemberwiseClone',
 'Overloads',
 'ReferenceEquals',
 'ToString',
 '__class__',
 '__delattr__',
 '__dir__',
 '__doc__',

Suspecting it might have something to do with the fact that said script was done for pythonnet 2.3.0, I tweaked it a bit using the documentarion:

from pythonnet import load
load('netfx')
import clr
clr.AddReference(R'C:\Users\XXXXX\Documents\XXXXX\XXXXX.dll')

from OwnedPackage.Compression import QuickLZ

Now the import fails, giving me an error that says that RGiesecke.DllExport.Metadata wasn't found (see below).

What commands did you run to trigger this issue? If you can provide a

import clr
clr.AddReference(R'C:\Users\XXXXX\Documents\XXXXX\XXXXX.dll')
from OwnedPackage.Compression import QuickLZ

QuickLZ.compression()

If there was a crash, please include the traceback here.

Traceback (most recent call last):
  File "C:\Users\XXXXX\Documents\XXXXXX\prueba.py", line 6, in <module>
    from OwnedPackage.Compression import QuickLZ
  File "<frozen importlib._bootstrap>", line 1229, in _handle_fromlist
System.IO.FileNotFoundException: No se puede cargar el archivo o ensamblado 'RGiesecke.DllExport.Metadata, Version=1.0.0.0, Culture=neutral, PublicKeyToken=8f52d83c1a22df51' ni una de sus dependencias. El sistema no puede encontrar el archivo especificado.
Nombre de archivo: 'RGiesecke.DllExport.Metadata, Version=1.0.0.0, Culture=neutral, PublicKeyToken=8f52d83c1a22df51'
   en System.ModuleHandle.ResolveType(RuntimeModule module, Int32 typeToken, IntPtr* typeInstArgs, Int32 typeInstCount, IntPtr* methodInstArgs, Int32 methodInstCount, ObjectHandleOnStack type)  
   en System.ModuleHandle.ResolveTypeHandleInternal(RuntimeModule module, Int32 typeToken, RuntimeTypeHandle[] typeInstantiationContext, RuntimeTypeHandle[] methodInstantiationContext)
   en System.Reflection.RuntimeModule.ResolveType(Int32 metadataToken, Type[] genericTypeArguments, Type[] genericMethodArguments)
   en System.Reflection.CustomAttribute.FilterCustomAttributeRecord(CustomAttributeRecord caRecord, MetadataImport scope, Assembly& lastAptcaOkAssembly, RuntimeModule decoratedModule, MetadataToken decoratedToken, RuntimeType attributeFilterType, Boolean mustBeInheritable, Object[] attributes, IList derivedAttributes, RuntimeType& attributeType, IRuntimeMethodInfo& ctor, Boolean& ctorHasParameters, Boolean& isVarArg)
   en System.Reflection.CustomAttribute.GetCustomAttributes(RuntimeModule decoratedModule, Int32 decoratedMetadataToken, Int32 pcaCount, RuntimeType attributeFilterType, Boolean mustBeInheritable, IList derivedAttributes, Boolean isDecoratedTargetSecurityTransparent)
   en System.Reflection.CustomAttribute.GetCustomAttributes(RuntimeMethodInfo method, RuntimeType caType, Boolean inherit)
   en System.Attribute.GetCustomAttributes(MemberInfo element, Type type, Boolean inherit)
   en System.Attribute.GetCustomAttribute(MemberInfo element, Type attributeType, Boolean inherit)
   en System.Reflection.CustomAttributeExtensions.GetCustomAttribute[T](MemberInfo element, Boolean inherit)
   en Python.Runtime.MethodObject.AllowThreads(MethodBase[] methods)
   en Python.Runtime.ClassManager.GetClassInfo(Type type, ClassBase impl)
   en Python.Runtime.ClassManager.InitClassBase(Type type, ClassBase impl, ReflectedClrType pyType)
   en Python.Runtime.ReflectedClrType.GetOrCreate(Type type)
   en Python.Runtime.ModuleObject.GetAttribute(String name, Boolean guess)
   en Python.Runtime.ModuleObject.tp_getattro(BorrowedReference ob, BorrowedReference key)

AVS: El registro del enlace de ensamblado está desactivado.
Para habilitar el registro de errores del enlace de ensamblado, establezca el valor de Registro [HKLM\Software\Microsoft\Fusion!EnableLog] (DWORD) como 1.
Nota: existe una disminución del rendimiento asociada registro de errores del enlace de ensamblado.
Para desactivar esta característica, elimine el valor de Registro [HKLM\Software\Microsoft\Fusion!EnableLog].

I also run get_runtime_info() and got this:

Runtime: .NET Framework
=============
  Version:      <undefined>
  Initialized:  True
  Shut down:    False
  Properties:
    domain = 
    config_file = None

Could it be related? Maybe it's not finding my .NET Framework files, although they are in their default Windows location???