.NET (Core and Framework)

• I have created an interface with the right attributes:
  C#

  [ComVisible(true)]
  [Guid("12345678-3e60-4c56-abcd-13d4098434f7")]
  [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
  public interface IConvertor
  {
      string ConvertPatient(string s);
  }

• I have created a class that implements this interface:
  C#

  [ComVisible(true)]
  //[ClassInterface(ClassInterfaceType.None)]
  public class Convertor : IConvertor
  {
      public Convertor()
      { }
  
      public string ConvertPatient(string s)
      {
          return "Hello, " + s;
      }
  }

• In the .csproj file I added these:
  XML

  <Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
      <TargetFramework>net5.0</TargetFramework>
      <!-- Indicate the assembly is providing a COM server -->
      <EnableComHosting>true</EnableComHosting>
      <EnableRegFreeCom>true</EnableRegFreeCom>
  </PropertyGroup>
  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|AnyCPU'">
    <PlatformTarget>x86</PlatformTarget>
  </PropertyGroup>
  <ItemGroup>
      <PackageReference Include="Hl7.Fhir.R4" Version="3.6.0" />
  </ItemGroup>
  </Project>

Quote:

TlbExp : error TX0000 : Type library exporter encountered an error while processing 'hdmpcloud.ehealth.FhirTools.InterOp.Convertor, hdmpcloud.ehealth.FhirTools.InterOp'. Error: Type library exporter cannot load type 'hdmpcloud.ehealth.FhirTools.InterOp.Convertor' (error: Could not load file or assembly 'System.Runtime, Version=5.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The system cannot find the file specified. (Exception from HRESULT: 0x80070002)).

Quote:

RegAsm : error RA0000 : Failed to load 'C:_projects\HDMP\hdmpcloud.ehealth.FhirTools\InterOp\hdmpcloud.ehealth.FhirTools.InterOp\bin\Debug\net5.0\hdmpcloud.ehealth.FhirTools.InterOp.comhost.dll' because it is not a valid .NET assembly

• Is COM still possible in .NET 5?
• The documentation is for .NET in general, but they don't specify a version.