Initial situation

I made use of the Component Object Model (COM) in the .NET Framework before in order to use my C# class library in Delphi as shown in this YouTube tutorial, which worked surprisingly well. However, I now want to use .NET Core 6 instead.

Following the official tutorial from Microsoft "Expose .NET Core components to COM", I created this interface

using System.Runtime.InteropServices;

[ComVisible(true)]
[Guid(6775d93d-cf14-42b9-83db-425bac0acf4d)]
[InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
public interface IServer
{
    public string getHelloWorld();
}

and this class.

using System.Runtime.InteropServices;

[ComVisible(true)]
[Guid(d62bf794-d29e-4fcd-8637-994490264a93)]
public class Server : IServer
{
    public string getHelloWorld()
    {
        return "Hello World";
    }
}

After building the project, I executed this command to register all of my exposed .NET objects with COM.

regsvr32 MyProjectName.comhost.dll

The command executed successfully. I now tried to import the created .dll file in Delphi, like I did before with the class libraries written in .NET Framework (See timestamp of YouTube tutorial). However, Delphi runs into an error because it can't load the type library.

Edit 1: Godzilla-type breaking change

According to the official documentation...

Unlike in .NET Framework, there is no support in .NET Core or .NET 5+ for generating a COM Type Library (TLB) from a .NET assembly. The guidance is to either manually write an IDL file or a C/C++ header for the native declarations of the COM interfaces. If you decide to write an IDL file, you can compile it with the Visual C++ SDK's MIDL compiler to produce a TLB.

... there is no support in .NET Core for generating a typelib.

Edit 2: MIDL compiler

However, there is still a way to manually produce a TBL file by using the MIDL compiler. As you can read up in the official documentation, the MIDL compiler processes an IDL file to generate a type library. With that beeing said, I created this IDL file by using this guide.

[
    uuid(a93d03e0-9adf-4a2d-93e3-0ccfc2d8e1a6),
    lcid(0x0409),
    version(1.0),
]
library MyProjectName
{
    importlib("stdole.tlb"); 
    [
        uuid(16292ce5-ccd1-405d-9a70-ace42152bb15),
        oleautomation,
        dual
    ]
    interface IServer: IUnknown {
        HRESULT getHelloWorld([out, string] IServer** string);
    };
};

However, I get an error when I execute the following command to generate the .tlb file.

midl myProjectName.idl /tlb myProjectName.tlb

> midl : command line error MIDL1005 : cannot find C preprocessor cl.exe

Issue: I searched for cl.exe on my Computer but couldn't find anything.

Q.: Does anybody have an idea on how I could solve my problem? I highly appreciate any kind of help, cheers!