procedure Update; override;
virtual void __fastcall Update();
Forces the control to update.
Update repaints any part of the control surface that is out of date. Normally, updates occur automatically, but an Update call may be necessary before lengthy processing that might interfere with automatic updates. Calling Update unnecessarily can increase overhead and cause screen flicker.
Update only repaints areas of the control the have been determined to be out of date. To force immediate repainting of the entire control, call the Repaint method. To notify a control that it is out of date (without forcing an immediate repaint), call the Invalidate method.