Trapping a double click on CListCtrl

Glenn T. Jayaputera -- gtj@nunkeen.apana.org.au
Friday, May 03, 1996

Env: VC4.0/Win95

How do I trap which item index (on CListCtrl object) on which the user
has double clicked.  I can trap the double click notification but how
do I get the info on which item index was that.  I tried to cast the
*pNMHDR to NM_LISTVIEW *  as follows

  NM_LISTVIEW *pNMLISTVIEW = (NM_LISTVIEW *) pNMHDR

but the iItem member of pNMLISTVIEW contains some obsecure number...

thanks for your pointers
glenn tesla

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Norman L Covington -- doubleM@cris.com
Saturday, May 04, 1996

[Mini-digest: 8 responses]

Glenn T. Jayaputera wrote:
> 
> Env: VC4.0/Win95
> 
> How do I trap which item index (on CListCtrl object) on which the user
> has double clicked. ...

Glenn:

A method I have used successfully is:
  int nItem = 
GetNextItem(-1,LVNI_ALL|LVNI_FOCUSED|LVNI_SELECTED);

Hope it helps,

Norman
doubleM@concentric.net
-----From: "Frederic Steppe" 

Assuming that a double click sets the focus to the clicked item before 
notification, just call GetNextItem(-1, LVNI_FOCUSED) to get the focused 
index, which should be the clicked index.

Frederic Steppe (frederics@msn.com)
-----From: Vincent Mascart <100425.1337@CompuServe.COM>

Glenn,

You can keep track of the currently selected item in a class member using the
following code :

in message map:
ON_NOTIFY(LVN_ITEMCHANGED, IDC_LIST, OnItemchangedList)

// m_lvList Listview notification handling
//
void CDosListView::OnItemchangedList(NMHDR* pNMHDR, LRESULT* pResult) 
{
	NM_LISTVIEW* pNMListView = (NM_LISTVIEW*)pNMHDR;

	if(pNMListView->uNewState & (LVIS_SELECTED | LVIS_FOCUSED))
	{
		m_iItem = pNMListView->iItem;
	}
	*pResult = 0;
}

-----From: "asha" 

void X::OnDblClickList(NMHDR* pNMHDR, LRESULT* pResult) 
{
	// TODO: Add your control notification handler code here
	POINT pt ;

	LV_HITTESTINFO HitTestInfo ;

	::GetCursorPos(&pt) ;

                  // m_List represents your list control

	m_List.ScreenToClient(&pt) ;

	HitTestInfo.pt = pt ; // in client coordinates
	
	if(m_List.HitTest(&HitTestInfo) != -1 )
	{
     	       // These three flags together determine if the position is over 
                         // the item 
                           if(HitTestInfo.flags == (LVHT_ONITEMSTATEICON | 
                                         LVHT_ONITEMLABEL | 
                                         LVHT_ONITEMICON  ))
		{
			// You can get the item for processing from the HitTestInfo 
                                                        // structure
			m_List.GetItemState(HitTestInfo.iItem,LVIS_SELECTED) ;
                                      }
	}  // end if hit test is successful

	*pResult = 0;
}

 
-----From: Mario Contestabile 

yourlistview::OnRButtonDown(UINT nFlags, CPoint point)   
    or
yourlistview::OnLButtonDblClk(UINT nFlags, CPoint point) {

 LV_HITTESTINFO lvh; 
 lvh.pt = point;
 if(m_ListCtrl.HitTest(&lvh) == -1) return;
 CString Name = m_ListCtrl.GetItemText(lvh.iItem, 0); // Name contains column 0 
string
}

mcontest@universal.com

-----From: Frank McGeough 

The only thing that's there is the NMHDR, unfortunately not the 
NM_LISTVIEW*.

I don't know what the best way is to do this but I solved my problem with
dealing with Right clicks and double clicks by grabbing the point on 
button down and then doing an evaluation in the function of interest
(doubleclick, rightclick) 

// for tree control
    UINT flags = TVHT_ONITEM;
    CTreeCtrl& treeCtrl = GetTreeCtrl( );

    // m_pt is a POINT that was set in button down methods
    HTREEITEM treeItem = treeCtrl.HitTest( m_pt, &flags );
    if (treeItem != NULL)
    {
           // do work
    }	
 

// for list control
    UINT flags = TVHT_ONITEM;
    CListCtrl& listCtrl = GetListCtrl( );

    int index = listCtrl.HitTest( m_pt, &flags );
    if (index != -1)
    {
           // do work
    }

As I had minimal information when I solved the problem in this
way, I'd appreciate any discussion of other approaches to this
problem and especially an explanation of why the pointer that I
really want (NM_TREEVIEW* or NM_LISTVIEW*) isn't passed for a
right click or double click msg. The NMHDR structure seems
pretty useless by itself and when I run into things that I
think are useless that usually means that I'm missing something.
Explanations?
__________________________________________________
Frank McGeough      fm@synchrologic.com
Synchrologic, Inc. (http://www.synchrologic.com/)
Voice: 404.876.3209            Fax: 404.876.3809
-----From: Doug Reese 

I don't even use the pNMHDR.  Here's a sample from my code; m_ctlResultList
is a CListCtrl:

        // get selected item
	int nItem, nFlags;
	nFlags = LVNI_SELECTED;
	nItem = m_ctlResultList.GetNextItem(-1, nFlags );
	if ( nItem != -1 )
        {
                // nItem is the 0 based index of the selected item
        }

Hope this helps

Doug Reese

-----From: erik.heuer@ks-t.no (Erik Heuer)

Try using CListCtrl::HitTest

Erik Heuer, Kongsberg Simulation & Training, 3600 Kongsberg, Norway
E-mail: erik.heuer@ks-t.no  Phone:(+47) 32735766 Fax:(+47) 32736965

---

Frederic Steppe -- FredericS@msn.com
Thursday, May 09, 1996

>Glenn T. Jayaputera wrote:
>> 
>> Env: VC4.0/Win95
>> 
>> How do I trap which item index (on CListCtrl object) on which the user
>> has double clicked. ...

> Precisions after reading the "[Mini-digest: 8 responses]"

For those who tried to find the clicked item using GetNextItem(-1, 
LVNI_SELECTED), just remember that a CListCtrl may have multiple selection, 
and the users don't always click on the first one.  Using 
GetNextItem(-1,LVNI_FOCUSED) seems better to me.

By the way, it REALLY seems to be the only simple solution, isn't it ?

Frederic Steppe (frederics@msn.com)

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