I posted this here for the OP, as they sent it by default as a question edit.
Instead of rewriting the COM server (written in 1992 using C ++ / MFC) to .Net, I decided to convert it to a CLR assembly. To take a COM assembly (add32.exe) and use it with a .Net client, we need to create a called shell. Run all the tools using the Visual Studio command prompt (as an administrator).
Step 1: Sign a COM Node with a Strong Name

Step 2: Convert the definitions found in the COM library to the CLR assembly
, COM, CLR Tlbimp.exe. Tlbimp.exe - (), , . - DLL . , .Net COM-.

3. ILDASM.EXE .

CLR, . dll .

, COM-, , , 2.
#using "Add32Pkg";
, COM:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.InteropServices;
using Add32Pkg;
namespace TestAdd32
{
class Program
{
[STAThread]
static void Main(string[] args)
{
Add32Server Add32 = new Add32Server();
Add32.Init(201);
}
}
}