[Lazarus] TMemo flicker

J├╝rgen Hestermann juergen.hestermann at gmx.de
Wed May 1 12:16:29 CEST 2013


Am 2013-04-30 20:45, schrieb Graeme Geldenhuys:
 > If that is the case, then it is a bug in LCL. Even if there are nested
 > Begin/EndUpdate calls, that should make no difference. As long as those
 > calls are in pairs, and as soon as the last EndUpdate is called, then
 > the whole component should refresh/repaint - that includes contents,
 > scrollbar adjustment etc.

Yes, after thinking about it a bit more there should be an internal Begin/EndUpdate somewhere in the corresponding LCL routine. I first thought that each Begin/EndUpdate pair causes code generation but actually it is the opposite (if nesting is allowed).


 > That's how it works in Delphi's VCL and in fpGUI. Nothing complicated or
 > tricky. Before you populate any GUI component with large amounts of
 > data, call BeginUpdate before and EndUpdate after.

Yes, if the *programmer* does multiple things to a GUI component. But here it was only a single assignment which should not require Begin/EndUpdate but this assignment seems to cause multiple things internally which make it flicker .




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