Text Box To Combo Box Puzzle 1

[Jackvmae]

On a demo application I saw a really neat trick. I'd like to incorporate it into my application, but I can't find out how it's done. I can't find the code anywhere. Can anyone explain this "puzzle?"

On a form is an ordinary text box. No drop down arrow like your typical combo box. However when you click in the text box then it turns into a combo box complete with the arrow and drop down. When you tab out of the combo box it turns into a text box again. Can anyone provide code for how this is done?

As I said, I can't find code for this anywhere in this demo application. No event procedure. No module code. No calls to a procedure or function.
Jack

 

[Steve101]

Probably done by overlaying a text control and a combo control over the same space on a form, and playing with the visible property on the various associated OnEnter, OnExit, GotFocus, LostFocus events.

Basically, when the text box is exposed and receives the focus, an event would be triggered which exposes the combo, moves the focus to it, then makes non visible the text box. When the combo is exited, the process is reversed.


Why not give this a try; I wouldnt think it was too hard to emulate, and would be a nice little exercise in understanding a number of the form based contol's events.

Steve Lewy
Solutions Developer
steve@lewycomputing.com.au
(dont cut corners or you'll go round in circles)