[SOLVED]advice: Let user change a grids' options without repainting it
lazarus / 31-LCL

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kinlion · 2018-11-24 10:30

I want to draw merged cells with TStringGrid, and write drawing code
in a StringGrid's OnDrawCell event. But after calling the event
handler, TStringGrid will draw the cell border. That's not my want.
Then I remove goHorzLine from the StringGrid's Options in OnDrawCell,
unfortunately this maks a dead-loop because after setting the Options,
the StringGrid will be fully repainted.

Since FOptions is private of TCustomGrid, I have to add a public
procedure to TCusomGrid to modify the Options.

Maybe it's better to let TCustomGrid have a way to modify Options
without repaint?

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wp · 2018-11-24 10:33

Did you try to call Grid.BeginUpdate before and Grid.EndUpdate after
your changes? They should suppress any redraw requests in between.

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kinlion · 2018-11-24 10:36

let me try

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kinlion · 2018-11-24 10:40

YES, BeginUpdate/EndUpdate works well. 
Thank you very much!
Quote from: wp on November 24, 2018, 11:33:00 amDid you try to call
Grid.BeginUpdate before and Grid.EndUpdate after your changes? They
should suppress any redraw requests in between.