Question about the implementation of "Marshal.GetActiveObject(System.String)" method

I'm trying to connect to a running Solid Edge instance, but I am getting the following error:

System.MissingMethodException: 'Method not found: 'System.Object System.Runtime.InteropServices.Marshal.GetActiveObject(System.String)'

I've been searching about this error and I found that:

"API was originally removed from .NET Core since COM support was not included.", but it is on .NET framework.
And "that API is a simple wrapper over the Running Object Table (ROT)" so there is a solution pulling function directly from source code and modifying the Marshal class.

I want to make another solution, more accurate for my project. The idea is to make a DLL with .NET Framework 4.8.1 and then use it in another projects that are programmed with .NET Core 7.

I wrote this code snippet for the DLL:

using System;
using System.Runtime.InteropServices;
 
namespace SolidEgde.OpenSDK
{
    public static class Communication
    {
        /// <summary>
        /// Connects to or starts a new instance of Solid Edge.
        /// </summary>
        /// <param name="startIfNotRunning"></param>
        /// <returns>
        /// An object of type SolidEdgeFramework.Application.
        /// </returns>
        public static SolidEdgeFramework.Application Connect(bool startIfNotRunning)
        {
            SolidEdgeFramework.Application application = null;
 
            try
            {
                // Attempt to connect to a running instance of Solid Edge.
                application = (SolidEdgeFramework.Application)Marshal.GetActiveObject(PROGID.SolidEdge_Application);
            }
            catch { throw; }
 
            if (application != null)
                application.Visible = true;
 
            return application;
        }
    }
    public static class PROGID
    {
        public const string SolidEdge_Application = "SolidEdge.Application"; // HKEY_CLASSES_ROOT\SolidEdge.Application
    }
}

And then I call It from a test project, like this:

namespace Testeo
{
    class Program
    {
        static void Main(string[] args)
        {
            SolidEdgeFramework.Application application = null;
 
            application = SolidEgde.OpenSDK.Communication.Connect(true);
        }
    }
}

But I get the error mentioned at the beginning.

PS: in my project I am trying to connect to an instance of the Solid Edge CAD program.

Solution

Based on the comment of @Hans Passant, I search more info about legacy dll .NET Framework components and .NET Core integration and the answer is:

No, It is not possible to have both on a project in a safe way.

Why?

They target a different set of assemblies (mscorlib vs. System.Runtime) which causes incompatibilities since all usages of types are prefixed with the assembly the type is from.
.NET Core can reference .NET Framework assemblies. This allows to reference the assembly and compile successfully. BUT this doesn't guarantee a successful execution on runtime, since .NET Core doesn't provide all the APIs from .NET Framework.

References to this problem: