Delphi Tutorial #112 - Tab Order

Alister Christie is a Delphi MVP (Most Valued Professional), Consultant, Developer, Trainer, Presenter, and Author. He has presented at ADUG (Australasian Delphi Users Group) Symposia and Code Rage Conferences for many years. Alister holds a degree in Mathematics and Computer Science from Victoria University, Wellington. He lives near Wellington, New Zealand.

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[MrPontiac]

I don't like manually managing the tab order of the components I place on a form. When I statically place a component, I've always expected the tab flow to follow how English is read. Left to Right, Top to Bottom. I don't ever want to go back to a form and have to manhandle it again, which I admit would be useful for some, but never for me.

Disclaimer; This code I wrote relies on SQLite to do the sorting. Most of the tools I write deal with this database engine, so, adding an extra layer for one-time init is acceptable IMO.

I have a single stand alone function, that when passed a tForm, it'll look at every tWincontrol object and put the Top, Left, and memory location of that component into a table that sits in memory. I then do a simple "select LeftPos, TopPos, Addr from TabOrderTable order by TopPos, LeftPos' and then assign the TabIndex of the component to whatever row count I'm on.

IE:
RowCounter:=1;
while not tbl.eof do begin

Comp.TabIndex:=RowCounter;
inc(RowCounter);
tbl.Next
end;

The one thing that you mention I hadn't thought of (Because it'd never come up) is the ordering of buttons that don't follow left-to-right notation. To get around that, I'd make a form level function that'd specifically be run AFTER this main sort that'd specifically put the buttons in whatever order I wanted.

Either that, I'd change the sorting algo to support which direction the order should go, and, allow for grouping components (GroupBox, Panel, etc) to be passed in instead of a tForm.