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Programming:

Event-driven programming can best be understood by contrasting it to
procedural programming.

· Applications written in procedural languages execute by
proceeding logically through the program code, one line at a time.
Logic flow can be temporarily transferred to other parts of the
program through the GoTo, GoSub, and Call statements, directing
the program from beginning to end.

· In contrast, program statements in an event-driven application
execute only when a specific event calls a section of code assigned
to that event. Events can be triggered by keyboard input, mouse
actions, the operating system, or code in the application. For
example, consider what happens when the user clicks a command
button named Command1 on a form. The mouse click is an event.
When the Click event occurs, Visual Basic executes the code in the
Sub procedure named Command1_Click. When the code has
finished running, Visual Basic waits for the next event.