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c#outlookvstooutlook-addin

Stopping acceptance of a meeting invite in Outlook using VSTO in certain circumstances

I have a VSTO extension written in C#. If someone gets a meeting invite, they are able to accept in several differnet ways, for example by choosing the dropdown choice on the Accept button and choose "Send Response Now".

I need to be able to stop the response in certain circumstances. I don't fully understand the relashionship and interactions between AppointmentItem and MeetingItem. The Send event doesn't seem to fire for either object type despite being wired up, but multiple Write events fire. Also multiple Property_Changed events fire (but this is to be expected). If I use cancel=true on MeetingItem_Write it still seems to send the response, and the invite disappears from the inbox.

I know VSTO is really old now, and the documentation is vague, but hopefully someone has tried to do this at some point in the past decade and can enlighten me.

Solution

  • Use Application.ItemSend event - MeetingItem will be passed in the Item parameter, and you'd be able to stop the submission by setting the (byref) Cancel parameter to true.