I'm trying to add iCal import support to my existing scheduling application which needs to support Windows XP, Vista, and 7. Writing iCal format is easy, but reading it is another story, mostly trying to convert times to local times with the complex TIMEZONE/TZID/RRULE syntax. Ideally Windows would have a native API for this, but I haven't found one.
I know Outlook 2007+ has an OpenSharedItem function that would work. I don't want to require users to have Outlook installed though, since my application "competes" with Outlook. I thought about writing a web service that would use Outlook on my web server to do this, but I know using Outlook OLE/COM objects from a service has issues, so that probably isn't an option either. I do own about 300 Exchange Server licenses, are there any APIs with Exchange that would maybe work better? I do notice when I email iCal files from GoToMeeting.com they say they were created with "Microsoft CDO for Microsoft Exchange", so I have a feeling they are doing something like this to avoid writing the format themselves.
My application is written in C++ using mostly native Win32 API, but I don't mind creating a .NET DLL for this, or even requiring users to have Internet access so I can post the file to my web server and have it return a converted format my app can use easily. My web server runs on Windows though, so anything Unix-based might be dificult. Other than that, I'm pretty open to options.
Update: I did find CDOEX but as I've never used it before, can anyone tell me where to start and if it can in fact do what I need? I don't really see much about iCal in the docs, and I'd need to install Exchange on my dev PC (not crazy about that) to start playing around with this API.
You can try to use Redemption (I am its author) - it allows to explicitly import iCal files using RDOAppointmentItem.Import(..., olICal).