c# Outlook 插件 vsto 在使用 OL2010 PIA 时访问 OL2016 Interop

Question

We have managed to build an outlook addin for 2010,2013 and 2016. We have created an OL2010 vsto project and fiddled with the .csproj file(1*). The problem is that few types were added in 2013/2016 and we can't access them. We only want to access them if the respective OL version is used of course.

As far as i understand the whole thing: The Interop assemblies are delivered with the addin. So its theoretically possible to inject some IL code or provide additional assemblies with the same namespace that provide those missing types. Since those Interop assemblies are only COM Wrapper and the functionallity relies on unmanaged code which is provided by the installed Outlook version they should get loaded seamlessly when imported correctly.

Is that somehow feasible? What could go wrong if i try this/deploy the addin to the client?
How could i proceed to determine if i need to use a higher version Interop Type?
How can i load the higher Interop Type?
How can i use it without conflicting existing types?
As i want Intellisense and static typing. I have to predefine those types and decorate them with Guid, CoClass, and TypeLibType. Will that be enough?

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(1*)(we changed the DebugInfoExeName and the OfficeVersion in the ProjectName.csproj file and built the respective installer with different virtual machines where the corresponding outlook versions are installed. Maybe there is an easier way? -> let me know!...sadly we can't use addin-express because of some reasons.

I would preferably not use the complete OL 2016 Interop Assemblies since it is throwing exceptions when used from other Threads than the main threads. And we have some synchronization code which has to be run in the background.

Thank you for any answers!

Answer 1

"Creating interops manually: In Visual Studio, just add a COM reference to an application of the Office 2000 suite to the project. This automatically creates the interop you need. But it is the point where your problem begins: a great number of classes and events are inaccessible, because a number of identical bugs in Office type libraries make Studio create the interop that will not work for you. You can disassemble the interop, make unavailable classes and events public, and recompile it (ildasm.exe and ilasm.exe). This is exactly the way Add-in Express version-neutral interops were created." source: https://social.msdn.microsoft.com/Forums/en-US/a95cd4e3-e619-4846-be2a-ce4c235ff457/is-it-possible-to-use-the-microsoftofficeinteropoutlook-that-comes-from-office-2010-with-all?forum=outlookdev

EDIT

Checkout this project https://github.com/netoffice/NetOffice-NuGet
It contains version neutral interop assemblies though the structure and namespaces dont match... But still could be useful.