Can I create an MSIX install for an Office COM Addin?

[StephenBullen]

Hi All,

I've written some COM Addins that target the Office VB Editor, using C#. I've created an MSI that installs them just fine but I'd like to put them on the Microsoft Store and it seems that only MSIX installs can integrate with the Store's payment and licensing processes.

I tried using the AI Packager to convert the MSI to an MSIX and it all seemed to work fine (all the COM entries showed up), but when I install the MSIX, there don't seem to be any registry entries created that would tell Office to load the COM Addin.

I guess that's because of the Registry virtualisation built into MSIX, but is there any way I can configure the MSIX install such that Office will see those registry entries when it starts?

Thanks

Stephen Bullen

[Catalin]

Hello Stephen and welcome to our forums,

You are indeed right. As I can see, it is not currently possible to package your addin as MSIX.

MSIX Office 365 (addins)

However, please note that you can also upload an MSI and an EXE to the store, as far as I'm aware:

How to publish your MSI and EXE setup applications in the Microsoft Store

Hope this helps!

Best regards,
Catalin

[StephenBullen]

Hi Catalin,

Thanks for the reply. It looks like the MS Store only integrates the ECommerce bit with MSIX installs. It will host an exe/msi, but I then need to involve third-party license and payment solutions.

I wonder if it would be possible/accepted to:
- Have a package containing a C# COM DLL and a Windows Form app (exe) referencing it
- Build an MSIX for the exe, with the RegistryWriteVirtualization disable for HKCU/Software/Classes
- When the App is launched, have it do all the COM registration for the DLL (either by writing entries directly, or by calling regasm), writing everything to HKCU

That should work, right?

Whether MS would allow such an approach to be shipped through the Store is another matter...

Stephen

[Catalin]

Hello Stephen,

I'm afraid I can not really tell if that will work, as you can't ever be "sure" of something.

I would advise giving this a test to see whether it will work or not.

One thing to be kept in mind is that your app will still run in the container so I'm not really sure about manually registering the DLLs.

Best regards,
Catalin