Hello everyone,

i am building an app for outlook

to get inputted email when compose an email

and then determine it is external or internal

i can got them

but know, i don't know how to determine

anyone know that can share with me some guide

Thanks in advance,

QP

Its depends what your definition of Internal is at compose time all you can do is check the Sender and Recipients of a Message and see if those email addresses resolve to an entry in your global Address list eg https://msdn.microsoft.com/en-us/library/office/ff862796.aspx. A message can have both Internal and External recipients so its gets quite complicated at that level.

Cheers
Glen