Registering COM referenced DLLs on a build server

Question

We're developing a C# application that references a few COM libraries (AutoIT for example).

I am including all referenced components under source control, in a 3rd party "Libs" folder.

The problem is that COM dll's don't have a HintPath property in the .csproj file, and i assume these must be manually registered using regsvr32 (or using a script of some sort).

I am currently looking into creating an MSBuild script that will run before every build, however i couldn't figure out if i should be manually calling regsvr32.exe or use some predefined MSBuild task?

Currently, this is what i've attmpted as a test:

 <?xml version="1.0" encoding="utf-8"?>
<Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003" DefaultTargets="Build">
  <ItemGroup>
    <MyAssemblies Include="D:\*.dll" />
  </ItemGroup>
  <Target Name="Build">
    <RegisterAssembly
      Assemblies="@(MyAssemblies)" >
    </RegisterAssembly>
  </Target>
</Project>

This generates errors that the DLLs i've placed in the given folder are not valid DLLs.

What is a good solution for this problem?

EDIT:

Projects that reference COM dlls have something similar to this in the .csproj file:

<COMReference Include="AutoItX3Lib">
      <Guid>{F8937E53-D444-4E71-9275-35B64210CC3B}</Guid>
      <VersionMajor>1</VersionMajor>
      <VersionMinor>0</VersionMinor>
      <Lcid>0</Lcid>
      <WrapperTool>tlbimp</WrapperTool>
      <Isolated>False</Isolated>
    </COMReference>

This does not include any hint path as other managed assemblies, so on a build server, the referenced COM dll is not found.

When registering the COM dll on the build server using REGSVR32, the build succeeds.

Answer 1

For my original answer to a similar question see: TFS Build server and COM references - does this work?

A better option for build servers may be to use the COMFileReference item in your project file instead of COMReference. An example would look like this:

<ItemGroup>
   <COMFileReference Include="MyComLibrary.dll">
     <EmbedInteropTypes>True</EmbedInteropTypes>
   </COMFileReference>
</ItemGroup>

The COM dll doesn't need to be registered on the machine for this to work.

Each COMFileReference item can also have a WrapperTool attribute but the default seems to work fine. The EmbedInteropTypes attribute is not documented as being applicable to COMFileReference, but it seems to work as intended.

See https://docs.microsoft.com/en-ca/visualstudio/msbuild/common-msbuild-project-items#comfilereference for a little more detail. This MSBuild item has been available since .NET 3.5.