{
    INT index = LISTBOX_GetItemFromPoint( descr, x, y );

    TRACE("[%p]: lbuttondown %d,%d item %d, focus item %d\n",
          descr->self, x, y, index, descr->focus_item);

    if (!descr->caret_on && (descr->in_focus)) return 0;

    if (!descr->in_focus)
    {
        if( !descr->lphc ) SetFocus( descr->self );
        else SetFocus( (descr->lphc->hWndEdit) ? descr->lphc->hWndEdit : descr->lphc->self );
    }

    if (index == -1) return 0;

    if (!descr->lphc)
    {
        if (descr->style & LBS_NOTIFY )
            SendMessageW( descr->owner, WM_LBTRACKPOINT, index,
                            MAKELPARAM( x, y ) );
    }

    descr->captured = TRUE;
    SetCapture( descr->self );

    if (descr->style & (LBS_EXTENDEDSEL | LBS_MULTIPLESEL))
    {
        /* we should perhaps make sure that all items are deselected
           FIXME: needed for !LBS_EXTENDEDSEL, too ?
           if (!(keys & (MK_SHIFT|MK_CONTROL)))
           LISTBOX_SetSelection( descr, -1, FALSE, FALSE);
        */

        if (!(keys & MK_SHIFT)) descr->anchor_item = index;
        if (keys & MK_CONTROL)
        {
            LISTBOX_SetCaretIndex( descr, index, FALSE );
            LISTBOX_SetSelection( descr, index,
                                  !descr->items[index].selected,
                                  (descr->style & LBS_NOTIFY) != 0);
        }
        else
        {
            LISTBOX_MoveCaret( descr, index, FALSE );

            if (descr->style & LBS_EXTENDEDSEL)
            {
                LISTBOX_SetSelection( descr, index,
                               descr->items[index].selected,
                              (descr->style & LBS_NOTIFY) != 0 );
            }
            else
            {
                LISTBOX_SetSelection( descr, index,
                               !descr->items[index].selected,
                              (descr->style & LBS_NOTIFY) != 0 );
            }
        }
    }
    else
    {
        descr->anchor_item = index;
        LISTBOX_MoveCaret( descr, index, FALSE );
        LISTBOX_SetSelection( descr, index,
                              TRUE, (descr->style & LBS_NOTIFY) != 0 );
    }

    if (!descr->lphc)
    {   //  See rev 40864 use Ptr for 64 bit.
        if (GetWindowLongPtrW( descr->self, GWL_EXSTYLE ) & WS_EX_DRAGDETECT)
        {
            POINT pt;

        pt.x = x;
        pt.y = y;

            if (DragDetect( descr->self, pt ))
                SendMessageW( descr->owner, WM_BEGINDRAG, 0, 0 );
        }
    }
    return 0;
}

ReactOS Development > Doxygen