old problem with CListCtrl::EditLabel

[Mike Pliam]

I have looked over many posts and articles on this problem without being able to solve it. I have a CListCtrl created with the following styles:

	DWORD dwListStyle = LVS_REPORT | LVS_SORTASCENDING | LVS_SHOWSELALWAYS | WS_CHILD | WS_VISIBLE | LVS_EDITLABELS ;

When I attempt to edit an entry, it appears to edit just fine, but when I hit return following the edit, the former label reappears.

I have attempted to follow the advice posted by others indicating the need for 'handling' LVN_BEGINLABELEDIT and LVN_ENDLABELEDIT.

http://www.codeguru.com/forum/showth...trl+edit+label

http://www.codeguru.com/Cpp/controls...icle.php/c897/

My attempts to do this look like this:

// in class header
//..
	CListCtrl m_MyListCtrl;
//..

// in class implementation
// void MyClass::Rename()
{
//..
	int nItem;
	nItem = m_MyListCtrl.GetNextItem(-1, LVNI_SELECTED);

//..
	m_MyListCtrl.SendMessage(LVN_BEGINLABELEDIT, 0, 0);
	m_MyListCtrl.EditLabel(nItem);  // how to make edit permanent ?
	m_MyListCtrl.SendMessage(LVN_ENDLABELEDIT, 0, 0);
//..

There are no errors encountered. The label appears to edit properly, but when leaving the item, the old label reappears.

Please help.

[Igor Vartanov]

Mike, don't you see a difference between "handling LVN_xxx" and "sending LVN_xxx". In LVN_, N stands for notification. Notifications are control "callback" messages, not command messages.

Did you read this Editing listview subitems using LVM_GETEDITCONTROL that golanshahar recommended there in the link you found?

[Mike Pliam]

Thanks for pointing out my misinterpretation of 'handle'.

Yes, I have read and reread the references noted and have experimented extensively, especially:

Editing listview subitems using LVM_GETEDITCONTROL
By Reg Anderson November 21, 1998
http://www.codeguru.com/Cpp/controls...cle.php/c1077/

You'll notice in the many comments accompanying this article that the method proposed, which is devised using CListView, doesnt work with CListCtrl.

My app is based on a CView with a pane (CWorkspaceWnd) derived from CDockablePane containing a CListCtrl member that does all the heavy lifing. It works fine except that the item edits disappear as noted by myself and many others.

I have tried to add Reg Anderson's ListEditView.h and ListEditView.cpp to my test app, but it will not compile (VS 2010), allegedly not recognizing CListVew as a class. Consequently, a connot substitute the CWorkdspaceWnd member, CListCtrl m_wndWorkspaceList, with CListEditView m_m_wndWorkspaceList. So that approach appears to be a dead end.

My next effort was to add the CLVEdit class of Reg Anderson and implement

	afx_msg void OnEndLabelEdit(NMHDR* pNMHDR,LRESULT* pResult);
	afx_msg void OnBeginLabelEdit(NMHDR* pNMHDR,LRESULT* pResult);
}

identical to the method used by Anderson in his CListEditView class. This compiles but the edits still disappear as before. Incidently, I am only interested in editing the item in the first column, not any of the subitems.

I have attached a demo program for anyone interested in trying to get this to work.

[Arjay]

Mike, why don't you use the sample I made for you about a year or two ago?

[ovidiucucu]

If you don't want to edit sub-items and don't want to change some other default behavior, the only one notification message to be handled is LVN_ENDLABELEDIT:

void CEditableListCtrl::OnLvnEndlabeledit(NMHDR *pNMHDR, LRESULT *pResult)
{
   NMLVDISPINFO *pDispInfo = reinterpret_cast<NMLVDISPINFO*>(pNMHDR);
   // If the item label text has been modified...
   if(NULL != pDispInfo->item.pszText)
   {
      //... let's put it in the list! 
      SetItemText(pDispInfo->item.iItem, 0, pDispInfo->item.pszText);
   }
   *pResult = 0;
}

Aside notes:

1. Every compiler "allegedly not recognize CListVew as a class" just because the header file where CListVew class is defined (<afxcview.h>) is not included; anyhow, here you need CListCtrl and not CListView.
2. In my example, I didn't handle LVN_ENDLABELEDIT in the parent window class, but the reflected message (=LVN_ENDLABELEDIT) in a class derived from CListCtrl; this is a little bit more OOP approach; additionaly you may notice that the Wizard will help you more in this case.

[Mike Pliam]

Thanks, Ovi. Remarkably simple and effective solution.

I now find that I need to identify the original (pre-edited) item label and have been having trouble doing that. I've tried :

void CEditableListCtrl::OnLvnBeginlabeledit(NMHDR *pNMHDR, LRESULT *pResult)
{
	NMLVDISPINFO *pDispInfo = reinterpret_cast<NMLVDISPINFO*>(pNMHDR);
	if(NULL != pDispInfo->item.pszText)
	{
		//... let's save it for later use
		m_csItemText = pDispInfo->item.pszText;
		m_csOldName = m_csItemText;

	}
	*pResult = 0;
}

but obviously I havn't figured out how to get the initial (m_csOldName) because this code invariably leads to m_csOldName as empty.

Appreciate any suggestions.

[ovidiucucu]

If you really, really need to "keeep in mind" the old label text, you can do something like this:

void CEditableListCtrl::OnLvnBeginlabeledit(NMHDR *pNMHDR, LRESULT *pResult)
{
   NMLVDISPINFO *pDispInfo = reinterpret_cast<NMLVDISPINFO*>(pNMHDR);
   m_strOldLabelText = GetItemText(pDispInfo->item.iItem, 0);

   *pResult = 0;
}

Usually that's not necessary.

Basically, to make a listview control with editable item labels, we have only to:

1. Set the LVS_EDITLABELS style;
2. Handle LVN_ENDLABELEDIT; if the label text...
   
   • ...is unchanged, pDispInfo->item.pszText is NULL;
   • ...has been edited, pDispInfo->item.pszText is not NULL, then use its value to set the list item text.

All the rest is made by the control itself,
Probably, handling LVN_ENDLABELEDIT is let up to programmer, to allow performing additional formatting and validation.

[VladimirF]

{
	//... let's save it for later use
	m_csItemText = pDispInfo->item.pszText;
	m_csOldName = m_csItemText;
}

but obviously I havn't figured out how to get the initial (m_csOldName) because this code invariably leads to m_csOldName as empty.

This code should give you the NEW label, if you look closely...
But before you set the new text to that item, you sure can get its current text.

[Mike Pliam]

Thanks for the great help. The reason I need both old and new names is that this step is preliminary to changing the name of an item in another database.