I reviewed that blog and continued to google LockWindowUpdate (LWU) and related API calls and sure enough on one of them that site has a much better explaination: Turns out that LWU can only be used by one window on the desktop. It is used for drag operations often and if there is a conflict one will not do as intended. This could affect redrawing a window or not seeing a drag operation. Finally, when LWU is set back so redraw is possible, the entire desktop is redrawn.
The consensus for a better way is to use WM_SETREDRAW which only affects the window that is passed. I settled on: SendMessage(Form.handle, WM_SETREDRAW, 0,0) to Lock and SendMessage(Form.handle, WM_SETREDRAW, 1,0) RedrawWindow( Form.handle, 0, RDW_FRAME + RDW_INVALIDATE + RDW_ALLCHILDREN + RDW_NOINTERNALPAINT); to UnLock/allow redraw Using them together in a try...finally block. Works as expected for my use. BTW, a simple Repaint does not work to replace the RedrawWindow call. Chuck Belanger > I don't see anything in that blog to suggest it is not useful purposes other > than drag operations. One comment says... > > "We use LockWindowUpdate for avoiding extensive redraw operations when > reorganizing child windows/controls in an window. Without it you can see the > windows changing position, with it you don't and you just go from one layout > to the new one without flickering." > > It sounds like the best method is to use DeferWindowPos but that looks much > more difficult to use. > > Ross. > > _______________________________________________ Delphi mailing list -> Delphi@elists.org http://lists.elists.org/cgi-bin/mailman/listinfo/delphi
