COM reference name changes across versions (Win7 CERTCLIENTLib to Win8 CERTCLILib)

Question

We have a Visual Studio 2012 project (C#) that uses multiple COM references. I am bringing it into Git and am having trouble figuring out how to handle the COM references. If I add the COM references in the typical way, (Add Reference -> COM tab -> Select my references), the following situation occurs:

Visual Studio adds a mention of the references in the *.csproj file which includes a GUID field and version field. From this, I take it that Visual Studio looks in the windows\system32 folder and finds the requisite DLLs at build time. On some development PCs, we have windows 8 and on others we have Windows 7 and it turns out that each version of Windows references different versions of COM DLLs. So, if I: 1) add the references on a Windows 8 PC; 2) commit the project to Git; 3) checkout the project on a Windows 7 pc; 4) attempt to build the project on the windows 7 pc -- the build fails. This is because the Windows 7 pc had different versions of the COM DLLs than are on the Windows 8 PC.

What is the best way to handle this situation? Should I manually copy the necessary COM DLLs into my project folder and version them in Git? If I do this, how would I handle updates that Microsoft makes to their DLLs? (Periodically check for difference in the windows\system32 folder?) And also -- which version would I copy into the project folder -- those that come with Windows 8 or Windows 7?

Answer 1

I don't see any major differences, both type libraries are at version 1.0 and have not changed that I know of since Vista. Adding the references on a Win7 machine produces the exact same reference nodes:

<COMReference Include="CERTCLIENTLib">
  <Guid>{372FCE32-4324-11D0-8810-00A0C903B83C}</Guid>
  <VersionMajor>1</VersionMajor>
  <VersionMinor>0</VersionMinor>
  <Lcid>0</Lcid>
  <WrapperTool>tlbimp</WrapperTool>
  <Isolated>False</Isolated>
  <EmbedInteropTypes>True</EmbedInteropTypes>
</COMReference>
<COMReference Include="CERTENROLLLib">
  <Guid>{728AB348-217D-11DA-B2A4-000E7BBB2B09}</Guid>
  <VersionMajor>1</VersionMajor>
  <VersionMinor>0</VersionMinor>
  <Lcid>0</Lcid>
  <WrapperTool>tlbimp</WrapperTool>
  <Isolated>False</Isolated>
  <EmbedInteropTypes>True</EmbedInteropTypes>
</COMReference>

But, as noted in the comment, the CERTCLIENTLib type library name was changed to CERTCLILib. The exact reason for these names changes are not that clear to me, it was possibly done to make it match the description attribute better. I've seen this happen once before.

This does not in any way affect the way the COM code works, it does however affect C# code since the type library importer picks the name of the type library as the namespace name for the declarations in the library. Which doesn't matter at all either, the Tlbimp.exe utility allows using the /namespace option to change the namespace name.

Unfortunately that option is not available when you add the reference directly and let the build system generate the interop library. You'll have to run Tlbimp.exe yourself to work around this. Do so from the Visual Studio Command Prompt:

cd \where\your\project\is\stored
tlbimp c:\windows\system32\certcli.dll

Add the generated DLL to source control and add a reference to it. Do make a note about this in your source code file, this may bite 10 years from now.