VSTO in .NET Core

Question

Microsoft recommends to develop Office add-ins using the new Office.JS Add-ins mainly because of cross-plataforming.

We all saw a new player arriving, .NET Core. If Microsoft used .NET Core to create VSTO cross-plataforms, it would be awesome. VSTO has the benefit to be much more tied to Excel's process (not as tied as VBA) than the asynchronous Office.JS. This would please a lot of VSTO/VBA developers as they wouldn't have to learn JavaScript/CSS/HTML and a new deploying paradigm.

VSTO is based on COM, but I believe it would be possible to extends the existing APIs on VSTO to support Linux and Mac. It is undeniable that a VSTO add-in running in Excel's process is better than an Office.JS add-in.

My questions is: Is there a huge technical reason why this is not possible or too hard to implement?

Prytaneum

COM is not supported by Linux and Mac,this is the reason why VSTO can't work on those platforms. – Bookplate

Answer 1

COM interop requires IDispatch in order to allow late binding to COM objects, which is for Windows only and obviously not a component that satisfies .NET Core's cross-platform compatibility. So .NET Core cannot integrate with Interop assemblies without this support for IDispatch.

Oly