[Bug 9155] New: CBN_SELCHANGE and WM_GETTEXT bug/"feature" in Windows
http://bugs.winehq.org/show_bug.cgi?id=9155 Summary: CBN_SELCHANGE and WM_GETTEXT bug/"feature" in Windows Product: Wine Version: CVS Platform: PC URL: http://source.winehq.org/source/dlls/user32/combo.c#L134 7 OS/Version: All Status: UNCONFIRMED Severity: minor Priority: P4 Component: wine-user AssignedTo: wine-bugs(a)winehq.org ReportedBy: megajocke(a)notsohotmail.com When writing code for a dialog that uses a combo box of type CBS_DROPDOWN I stumbled upon something strange in Windows XP. In the CBN_SELCHANGE notification from the combo box the text of the edit box has not updated yet, which means WM_GETTEXT or APIs that use it return the old value instead of the newly selected. This does happen to CBS_SIMPLE too as it has an edit control but does not happen to CBS_DROPDOWNLIST. I had a look in WINE's combo box code and it looks like in WINE the edit box text gets updated (line 1358) before the notification is sent (line 1374). So this means that WM_GETTEXT will return the current value instead of the previous one which it does in Windows. The problem with this that I can see is probably more that applications written for WINE won't work correctly in Windows as it is not a far fetch to assume that WM_GETTEXT would work in the CBN_SELCHANGE handler. Just changing it to how it work in Windows might break something in WINE if some dialog somewhere is using WM_GETTEXT, GetDlgItemText or GetWindowText to get the value from a combo box with edit control. For example, I saw code in the printer dialog that uses WM_GETTEXT. (But this doesn't matter if the combo is of DROPDOWNLIST type which I didn't check if it was or not) To "fix" it, all CBN_SELCHANGE references in WINE need to be checked (not that many) and then CB_NOTIFY needs to be moved before the if block. Is it really correct though that the combo box sends CBN_SELCHANGE even when the list box reported LBN_SELCANCEL? Maybe it should be the first thing to do in the first if block? Here is a page from Microsoft on this behaviour, and it seems like it has worked like that from the beginning, look at that stuff about Win32 :P. The article is not entirely accurate though as WM_GETTEXT would return the newly selected value in a CBS_DROPDOWNLIST: http://support.microsoft.com/default.aspx?scid=kb%3Ben-us%3B66365 Here is someone else who has discovered this "feature" in Windows: http://groups.google.com/group/microsoft.public.vc.mfc/browse_thread/thread/... And here someone proposes that the OP use it to get the old value, relying on this "feature": http://groups.google.com/group/comp.os.ms-windows.programmer.win32/browse_th... More: http://www.powerbasic.com/support/forums/Archives/Archive-000003/HTML/200208... /Joakim Asplund -- Configure bugmail: http://bugs.winehq.org/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are the assignee for the bug, or are watching the assignee.
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