Solution: LISTBOX with LBS_OWNERDRAW and WS_POPUP

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JohnFound

Joined: 16 Jun 2003
Posts: 3499
Location: Bulgaria

JohnFound 14 Nov 2010, 20:09

It is known fact, this combination doesn't work. The owner window never receive WM_MEASUREITEM and WM_DRAWITEM messages. If the listbox have WS_CHILD style set, everything goes OK.
This probably is bug in user32.dll, because other controls (for example LISTVIEW) behave properly.

So, the solution:

Code:

proc CreatePopupListbox, .parent
begin
        invoke  CreateWindowEx, 0,  cListboxClassName,  0,         \
                WS_CHILD or WS_VSCROLL or WS_SIZEBOX or            \
                LBS_NOINTEGRALHEIGHT or LBS_OWNERDRAWFIXED or      \
                LBS_HASSTRINGS,                                    \
                0, 0, 300, 120, [.parent], 0, [hInstance], 0
        mov     ebx, eax

; Strange magic in order to receive owner draw messages from popup listbox
        invoke  SetParent, ebx, 0
        invoke  GetWindowLong, ebx, GWL_STYLE
        and     eax, not WS_CHILD
        or      eax, WS_POPUP
        invoke  SetWindowLong, ebx, GWL_STYLE, eax
        invoke  SetWindowLong, ebx, GWL_HWNDPARENT, [.parent]

        return
endp

14 Nov 2010, 20:09

edemko

Joined: 18 Jul 2009
Posts: 549

edemko 15 Nov 2010, 10:02

JohnFound,
Why to use a WS_POPUP style for any control at all?

15 Nov 2010, 10:02

JohnFound

Joined: 16 Jun 2003
Posts: 3499
Location: Bulgaria

JohnFound 15 Nov 2010, 10:21

edemko wrote:

JohnFound,
Why to use a WS_POPUP style for any control at all?

Well, there is no difference between controls and non-controls in Windows. If you create the window with WS_CHILD it is "control", if you create it without WS_CHILD it is normal window.
You can use one "control" as a parent for other control.
In the case with the list box, I wanted to use it as a drop down pop up window in Fresh auto complete function, but I wanted the list box to be owner draw, so I faced this problem and also found solution, that can be useful for someone else.

15 Nov 2010, 10:21

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