Calling Event handlers from within Delphi

Part of an application that I have written searches a large file for
the occurrence of a string of text. I have an event handler for a
button that searches forward for the next occurrence of it.

I would like to call the event handler if the user presses the F3 key,
but am not sure of the syntax of how to call an event handler, or even if
you can. Those best guesses that I've tried return compiler error messages.
I have Delphi Developers Guide and Waite Group:How to, but have not
found any info as I'm not sure of exact section I should be looking at.

Any info in terms of how to call event handlers, page numbers for above
books or even code snippets would be very much appreciated.

Many thanks in advance for your time in replying.
delphi version=1.0
Martyn Lavender
BBC Pebble Mill
Email:Martyn.Lavender @