VSTO add-in for OL 2003 and 2007

[Joe Lakey]

I am working on an Outlook add-in that has custom forms and interacts
with web services. The current version is a managed (C#.net) COM add-
in, but I am running into a number of issues, most involving other add-
ins. I'm looking into two possible solutions: using a COM shim and
using VSTO. My understanding is that with a COM shim, there is minimal
rewrite of existing code, but that VSTO would allow me to use managed
code. I am required to have only one codebase for both Outlook 2003
and 2007 (and possibly future versions). Any advice would be greatly
appreciated.

 

[SvenC]

Hi Joe,

I am working on an Outlook add-in that has custom forms and interacts
with web services. The current version is a managed (C#.net) COM add-
in, but I am running into a number of issues, most involving other
add- ins. I'm looking into two possible solutions: using a COM shim
and using VSTO. My understanding is that with a COM shim, there is
minimal rewrite of existing code, but that VSTO would allow me to use
managed code. I am required to have only one codebase for both
Outlook 2003 and 2007 (and possibly future versions). Any advice
would be greatly appreciated.

I made the decision a while ago to use C++ to write a COM addin natively.
You have all the control you need and no unsolveable problems to
integrate in all Office versions from one addin.

So if you have enough knowledge on C++ and COM, it is worth
consideration.

 

[Ken Slovak - [MVP - Outlook]]

Both VSTO and shared, shimmed addins are managed code and can be written in
C#.

It's much harder if not impossible to support both Outlook 2003 and 2007 in
a VSTO addin unless you decide not to support the ribbon in Outlook 2007.

There are workarounds for using the ribbon in shared addins even when
compiled as Outlook 2003 addins.

If using managed code and a shared addin you definitely should shim it to
give it it's own AppDomain so crashes or problems in other addins don't get
yours disabled.