Is the textbox bound? If so, then do this in the AfterUpdate event of the combo:
Me.YourTexbox = Me!Email & "@" & Me.YourCombo
Assuming you have a field named "Email" in the underlying recordset. Also, make SURE to name the "email" control something other than "Email", since that could confuse Access. Instead, name it something like "txMyEmail", and bind it to the correct field.
This can cause issues, however, since after setting this value one time, your Email field would contain a value like "
[email protected]". If I then select ANOTER domain, it would do this:
"
[email protected]@antoth
erdomain.c
om"
You can parse off anything before the "@" sign, if need be ...
A better question is this - why not just store the Email and Domain in the table, and then build the email as needed? You can easily do this vis a query:
FullEmail: Email & "@" & Domain
Assuming your base table has two fields.