OpenEuphoria

Re: Multi-list behavior under win32lib

• Posted by jjnick at cvn.com Apr 23, 2001
• 362 views

----- Original Message -----
From: "Derek Parnell" <ddparnell at bigpond.com>
To: "EUforum" <EUforum at topica.com>
Subject: RE: Multi-list behavior under win32lib
> Hi "jjnick at cvn.com",
> you have discovered a bug - sort of. The main problem is that getIndex()
was
> only designed to be used on single-selection listboxes. It works fine it
> those cases. I know how to "fix" it to work with multi-select lists but
the
> problem I have is 'What do I return?' If multiple items are selected then
> the obvious choice is a sequence of indexes. But this might break some
code
> that assigns the return value to an atom or integer.  What do you guys
think
> I ought to do?
>
> My preference is to return a sequence of indexes when the list is a
> multiple-select type and an integer otherwise. An empty list would
indicate
> that nothing is selected.

I tried "getMultIndices( id )" just now and and it also doesn't provide the
correct result (don't know why I didn't try this last night!  ).  My
contention is that if multi-selection boxes are supported in win32lib, then
how come there isn't the facility to detect whether or not a user has
selected anything from the list accurately?  If I just call "getMultItems()"
without checking to see whether a user has selected an item first, an error
comes up in win32lib itself . . .  Anyway, you probably know all this, just
reiterating . . .

> Here is the Microsoft documentation on the LB_GETCURSEL message, which is
> currently being used in Win32lib. Please note the *Remarks* when used with
> multi-selection lists.
>
> -------------------------------------
> *LB_GETCURSEL*
> Send an LB_GETCURSEL message to retrieve the index of the currently
selected
> item, if any, in a single-selection list box.
>
> To send this message, call the SendMessage function with the following
> parameters.
>
> SendMessage(
>   (HWND) hWnd,              // handle to destination window
>   LB_GETCURSEL,             // message to send
>   (WPARAM) wParam,          // not used; must be zero
>   (LPARAM) lParam          // not used; must be zero
> );
>
> *Parameters*
> This message has no parameters.
>
> *Return Values*
> In a single-selection list box, the return value is the zero-based index
of
> the currently selected item. If there is no selection, the return value is
> LB_ERR.
>
> *Remarks*
> Do not send this message to a multiple-selection list box.
>
> To retrieve the indexes of the selected items in a multiple-selection list
> box, use the LB_GETSELITEMS message. To determine whether the item that
has
> the focus rectangle in a multiple selection list box is selected, use the
> LB_GETSEL message.
>
> If sent to a multiple-selection list box, LB_GETCURSEL returns the index
of
> the item that has the focus rectangle. If no items are selected, it
returns
> zero.
>
>
> -------------------------------------
>
> cheers,
> Derek Parnell
>
>
>
>
>