clistctrl sorting problem

[dima2]

hi,
I'm developing an MFC dialog based application.
in my dialog i have a CListCtrl object in which i've inserted 3 columns. Whenever I insert a new item in the list i set it's itemdata equal to it's index.
what i'm trying to do is sort the items in alphabetical order based on the text in a selected column.
so when the user clicks on the column the items should be sorted.

I trapped the LVN_COLUMNCLICK notification and in the hadling function i put the following:

void CMyDlg::OnColumnclickList(NMHDR* pNMHDR, LRESULT* pResult)
{
NM_LISTVIEW* pNMListView = (NM_LISTVIEW*)pNMHDR;

nSortedCol = pNMListView->iSubItem;
//nSortedCol is a static member variable of the class CMyDlg

m_list.SortItems(SortList, (LPARAM) &m_list);
*pResult = 0;
}

I defined the compare function as a static member as follows:
int CEmailNotDlg::SortList(LPARAM lParam1, LPARAM lParam2, LPARAM lParamSort)
{
CListCtrl* pListCtrl = (CListCtrl*) lParamSort;
CString strItem1 = pListCtrl->GetItemText(lParam1, nSortedCol);
CString strItem2 = pListCtrl->GetItemText(lParam2, nSortedCol);

int ret=-wcsicmp(strItem2, strItem1);
return ret;
}


Now here comes the question:
when I first click on a colum the sorting is carried out perfectly, HOWEVER if I click again the rows are switched randomly. What's going on??

i would really appreciate any sort of help

thx a lot

 

[BestBoy]

You can use callback fn to sort the data
I wrote like this..

create a structure with the columns...
for eg., i 've 3 columns first name, last name and term
typedef struct {
LPTSTR pszLastName;
LPTSTR pszFirstName;
LPTSTR pszTerm;
} ITEMDATA, *PITEMDATA;
and use this structure to fill the list control..

for eg to insert an item...
ITEMDATA m_pData[10];

m_pData = new ITEMDATA;
m_pData->pszLastName = "Sachin";
m_pData->pszFirstName = "Tendulkar";
m_pData->pszTerm = "1989-2002*";

m_ctlListView.InsertItem(i, "Sachin"
m_ctlListView.SetItemText(i, 1, "Tendulkar"
m_ctlListView.SetItemText(i, 2, "1989-2002*"
m_ctlListView.SetItemData(i, (LPARAM)m_pData);

OnColumnClick....
=================
NM_LISTVIEW* pNMListView = (NM_LISTVIEW*)pNMHDR;
m_ctlListView.SortItems(SortFunc,pNMListView>iSubItem);

and the call back fn...
=======================
int CALLBACK SortFunc(LPARAM lParam1, LPARAM lParam2, LPARAM lParamSort)
{
int nRetVal;

PITEMDATA pData1 = (PITEMDATA)lParam1;
PITEMDATA pData2 = (PITEMDATA)lParam2;


switch(lParamSort)
{
case 0: // Last Name
nRetVal = strcmp(pData1->pszLastName,
pData2->pszLastName);
break;

case 1: // First Name
nRetVal = strcmp(pData1->pszFirstName,
pData2->pszFirstName);
break;

case 2: // Term
nRetVal = strcmp(pData1->pszTerm, pData2->pszTerm);
break;

default:
break;
}

return nRetVal;
}

 

[n8nt]

When I try this solution (I get find that lParam1 and lParam2 are always zero.

Here is a snippet of my code.
typedef struct {
LPTSTR pszFeature;
LPTSTR pszVersion;
LPTSTR pszClient;
LPTSTR pszClientNode;
int numLicenses;
int usedLicenses;
} ITEMDATA, *PITEMDATA;

ITEMDATA m_pData[100];


static int CALLBACK MyCompareProc(LPARAM lParam1, LPARAM lParam2, LPARAM lParamSort)
{

ITEMDATA* p1 = (ITEMDATA*)lParam1;
ITEMDATA* p2 = (ITEMDATA*)lParam2;
CString s1 = p1->pszFeature;
CString s2 = p2->pszFeature;

TRACE(_T("Address of lParam1 is: %08x AND lParam2 is %08lx\n&quot, lParam1, lParam2);

return strcmp(strItem2, strItem1);

}

//
// I populated the ITEMDATA structure as follows..
//
ITEMDATA* pData = new ITEMDATA;
pData->pszFeature = featureInfo->feature_name;
pData->pszVersion = featureInfo->version;

//
// finally, here is what I did on the ItemClick
//
void CABBQCSLicViewerDlg::OnColumnclickList3(NMHDR* pNMHDR, LRESULT* pResult)
{
NM_LISTVIEW* pNMListView = (NM_LISTVIEW*)pNMHDR;
// TODO: Add your control notification handler code here

// Sort the list view items using my callback procedure.
m_ReportListCTRL.SortItems(MyCompareProc,
(LPARAM) pNMListView->iSubItem);

*pResult = 0;
}

//
//
// Incidenetally, where does the lParam1 and lParam2 parameter even come from in the callback function? I don't see how those parameters get setup. Maybe that is part of my problem, although, as far as I can tell I've implemented my code the same as the example.

I also noticed that m_pData was allocated as a fixed array, but also it was allocated using the new function. I did the same but don't see the need to have the fixed array of ITEMDATA structures. I tried it both ways, but still get zeroes in both the lParam1 and lParam2 parameters when I get to the static CALLBACK function. Needless to say, that causes an exception when I try to fetch the parameters from the ITEMDATA casts of Lparam1 and lParam2.

I sure hope someone will help with this one.

Thanks, Bob