Re: CListCtrl.GetNextSelectedItem doesnot seem to work.

From:
"Ashot Geodakov" <a_geodakov@nospam.hotmail.com>
Newsgroups:
microsoft.public.vc.mfc
Date:
Fri, 2 Mar 2007 16:41:52 -0700
Message-ID:
<eO3qbRSXHHA.4964@TK2MSFTNGP06.phx.gbl>
pj wrote:

I am infact deleting the set of selected fields. Is this a problem?


Yes, it's a problem. Take a look at the (simplified) source code for
CListCtrl:

POSITION CListCtrl::GetFirstSelectedItemPosition() const
{
    return (POSITION)(DWORD_PTR)( 1 + GetNextItem ( -1, LVIS_SELECTED ) );
}

int CListCtrl::GetNextSelectedItem(POSITION& pos) const
{
    DWORD_PTR nOldPos = (DWORD_PTR)pos-1;
    pos = (POSITION)(DWORD_PTR)(1+GetNextItem( (UINT)nOldPos,
LVIS_SELECTED ) );
    return (UINT)nOldPos;
}

Now play the MSDN sample with the first 3 items in the list selected, and
trying to remoe each one item.

Initial state:
List: 0, 1 and 2 items selected.

Call to GetFirstSelectedItemPosition() returns 0;

Loop:
First iteration
- GetNextSelectedItem(pos = 0) returns 0, pos set to 1.
- remove item 0.
- list has two selected items 0 and 1 ( old 1 became 0 and old 2 became 1
after removal of 0)

Second iteration
- GetNextSelectedItem( pos = 1 ) returns 1, pos set to 2
- remove item 1.
- List has one selected item 0.

Third iteration
- GetNextSelectedItem( pos = 2 ) returns -1, pos set to 0

End of loop, and you still have one item 0 in the list selected.

"pj" <praneshrj@gmail.com> wrote in message
news:1172873589.865602.285060@31g2000cwt.googlegroups.com...

On Mar 2, 3:44 pm, "Ashot Geodakov" <a_geoda...@nospam.hotmail.com>
wrote:

Hi,

If you remove all the code that you added to this sample (item
processing,
etc.), will it work as you describe it?

Is it possible that you process a selected item by removing it from the
list?

Can you run just the raw MSDN sample without any additional code and tell
us
if it behaves as you said?

thank you

"pj" <pranes...@gmail.com> wrote in message

news:1172870196.485691.129750@z35g2000cwz.googlegroups.com...

Hi,

I am trying to use this code from msdn to get the list of selected
rows in the container of the CListCtrl (multi select mode). It works
fine if the user selects 2 rows. But for more that that, it doesnot
work. "pos" will point to NULL after two rows.

MSDN code:
=========
POSITION pos = pList->GetFirstSelectedItemPosition();
if (pos == NULL)
  //TRACE0("No items were selected!\n");
else
{
  while (pos)
  {
     int nItem = pList->GetNextSelectedItem(pos);
     //TRACE1("Item %d was selected!\n", nItem);
     // you could do your own processing on nItem here
  }
}

Is this a bug or am I doing something wrong here.

Thanks,
-pj.- Hide quoted text -


- Show quoted text -


I am infact deleting the set of selected fields. Is this a problem?

pj

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