Re: CListBox question again

Sure.

First, the listbox is really just a list of strings that display vertically.
When one is selected an index to the string is passed back (most often
although you can get the string as well). When you assign a pointer to the
listbox item using SetItemDataPtr() or a data item using SetItemData() you
are just adding some extra information that you can retrieve later.

For example, if you have an array of objects that contain information about
the items you could do something like:

for(int i=0;i < m_Objects.GetCount(); ++i) {
    CObjectInfo *pInfo = m_Objects.GetAt(i);
    m_cList.AddString(pInfo.m_csText));
    m_cList.SetItemDataPtr(i,pInfo);
}

Then later when the user selects one of the items or when the selection is
changed or whatever messages you are hooking into you can call:

CObjectInfo *pInfo = m_cList.GetItemDataPtr(i);

To get the object back for that item in the listbox.

Of course this example is a little contrived since if you had the items in
an array you may not need to store them in the listbox as well, but it's the
same memory so it saves you from having to look it up in the array. Also,
the object stays the same even though some items in the list may be moved,
sorted, or deleted from the listbox so it gives you more flexibility in
retrieving the object pointer back.

When the object is deleted the listbox will be pointing to deleted memory
(bad) so you'd have to know that and not continue to use that pointer.
You'd also want to NOT delete it when the listbox is destroyed if it is
still being used as part of the original array or you'd mess up that
reference. I mostly just let the array do it's own clean up and the pointer
in the listbox is just another way of accessing the same memory.

You could also use SetItemData() and GetItemData() (that store and retrieve
a single value) to just store the original index into the array (in the case
m_Objects) so you could retrieve the pInfo pointer from the array itself
rather than storing it in the listbox item.

In either case you still have to use AddString() to put the actual string
into the listbox.

You could also look at this example:

http://msdn2.microsoft.com/en-us/library/fw2702d6(VS.80).aspx

(apologies ahead of time to all who won't like the (VS.80) in the URL, but
that's how it is...)

Hope this helps some...

Tom

"Al" <Al@discussions.microsoft.com> wrote in message
news:4AB53982-8643-4BB0-805E-4CDFE2F6F181@microsoft.com...