C# COM 库不能被引用

Question

Following the guidelines from Turn a simple C# DLL into a COM interop component , I've created a tiny C# COM server:

[ComVisible(true)]
[InterfaceType(ComInterfaceType.InterfaceIsDual)]
[Guid("410B8E64-27DB-40BD-8847-FC3A0E96147D")]
public interface IFactory
{
    int PlusOne(int i);
}

[ComVisible(true)]
[ClassInterface(ClassInterfaceType.None)]
[Guid("207FC3AB-0EFB-459A-B222-41E281F044F9")]
public class Factory : IFactory
{
    public int PlusOne(int i) => i + 1;
}

I've created as well a client C# project which just references this COM server. And here is the problem: COM reference is not working, in Dependencies->COM section it is marked with a yellow warning triangle without any further explanations, and types from the COM component are not available in the client code. These projects are published on github . Note, that COM server atomaticly registers itself (regasm) upon rebuild of the project. I'll appreciate any help. The answers like "you can reference your server as a .net assembly directly without need to use COM", are not acceptable, as this is just a test of a part of a bigger workflow which we need to establish.

Answer 1

The reason for inactive reference was found after examining compiler warnings and it was in explicit prohibition for .Net client to reference .Net COM server. There is such a possibility, though, as described here: https://docs.microsoft.com/en-us/samples/dotnet/samples/out-of-process-com-server/

I've checked, and this really worked fine, and it became possible for a .Net client to reference a Server.Contract.tlb from the example. As a bonus, Microsoft added the possibility for .Net Core targeting COM server to be loaded into COM Surrogate or to be run as out-of-process (standalone exe). This works indeed just for netcoreapp3.1 server, as when I've changed target framework to net48, no DllServer.comhost.dll (containing, most probably, proxy/stub code) was autogenerated as it did for netcoreapp3.1, the project property <EnableComHosting>true</EnableComHosting> obviously didn't have any effect.