Please explain what an outlook add-in is

Question

Can someone give me a quick explanation of when I would use Visual Studio 2008 Outlook 2007 Ad-In project type? and how would that compare to developing a bunch of outlook macros directly in outlook?

Basically, I want to have some sort of application read email (with attachments) from a pop3 email box, do some filtering/editing/validation of the subject/sender/content and then if certain conditions are met, save the attachments to a local file, and then add an entry into an SQL server database table (i.e. date/sender/subject/message).

Seems there are at least 10 different ways to do this....so between an outlook macro and a VS Office Project, how do I pick?

I am not clear, if I create this solution as a Visual Studio outlook add-in, where does it run? Is it loaded into outlook, does it run as a separate process and communicates back and forth with outlook? if outlook is not running, does it start it?

Answer 1

This is an example of an outlook add-in.. Personally, I don't see macros distributable.

Answer 2

An Outlook Add-on is a compiled component that uses the Outlook API to perform the tasks you need. A macro/VB script is an interpreted script that actually uses the same API. The add-on approach is better if you want to deploy your functionality.

When you work on an Outlook add-on in Visual Studio, you'll be creating a .NET component, which integrates into the Outlook application, which is written in C++ so uses COM. You'll have to be careful about managed/unmanaged types and releasing objects you retrieve from Outlook.

I have recently completed just such a tool, but I chose to use Add-in Express (http://www.add-in-express.com/). These guys provide a layer of abstraction over the [challenging] Outlook API and also provide some excellent support if you're stuck.

In my case, with Add-in Express, I "run" by setting Outlook as the application command to run, in the Project properties. Add-in Express sorts out the installation of the add-on within Outlook. So when I press "Run", Outlook starts and my add-in is displayed, which may be debugged in the normal fashion. I'm not sure how VSTO (Visual Studio Tools for Office) works in this respect - or at least, I can't remember.