1. CS 106 Computing Fundamentals II Chapter 69 “Event Loop”
Herbert G. Mayer, PSU CS
status 6/24/2013
Initial content copied verbatim from
CS 106 material developed by
CS professors: Cynthia Brown & Robert Martin

2. Syllabus
Events
Event Loop
Illustration

3. Events Events happen when your program is running
There are lots of events, like:
Opening the workbook
Clicking a command button
Typing in a text box or a spreadsheet cell
Etc. etc. etc.
If there is code for an event, something happens; otherwise, it is ignored

4. Event Loop
In VBA, when you run your program, the system is running in a continuous loop (a Do While TRUE loop) constantly looking for events and seeing if it has code for them
When an event for which there is an event procedure occurs, the VBA system executes the procedure, and then goes back to checking
The event loop stops running when you quit the program