Check and register Outlook as a default mail client programatically

Question

I'm developing a VSTO add-in for outlook. One part of this addin is a welcome screen that appears after first launch and on this screen I want to check if Outlook is a default mail client and if it's not provide users with the ability to set it as a default client. I know this can be done in Outlook's Tools/Options menu but I really would like to do that as a part of my app. Does anyone knows how to do that? Are there any classes/properties in VSTO that could help me with that or should I just edit registry settings and if so which ones are those.

Answer 1

You need to change the per-user mail-to setting in the registry, see e.g. here.