MessageBox after typing in a recipient in outlook with C#

Question

I would like to implement a window/message box that pops up in an outlook inspector once the sender has specified a recipient. How can I address outlook with Vsto that the message comes up before sending?

Answer 1

The MailItem.PropertyChange event is fired when an explicit built-in property (for example, Subject) of an object is changed. You are interested in the To, Cc or Bcc properties. Also you may find the PropertyChange event and MailtItem Properties thread helpful.