C / C++ / MFC

// your orders:
#define COL_COUNT 6               // Count of cols
bool g_arOrders[COL_COUNT] = {0}; // init state: no sorted cols yet
   
...
{
..
case WM_NOTIFY: 
  switch (((LPNMHDR) lParam)->code) {
    case LVN_COLUMNCLICK: {
      int iCol = ((LPNMLISTVIEW) lParam)->iSubItem;
      if (0 <= iCol && iCol < COL_COUNT) {
        g_arOrders[iCol] = !g_arOrders[iCol]; // order reversing,
                                              // will be used at comparing
        ListView_SortItems(hwndList, ListViewCompareProc, iCol);
      }
    }
    break;
...
}
...

typedef struct tagNOTATIONINFO
{
	int nEpoch;
	TCHAR szDateTime[20];
	TCHAR szEvent[100];
}
NOTATIONINFO;




int CALLBACK ListViewCompareProc(LPARAM lParam1, LPARAM lParam2, LPARAM lParamSort)
{
	NOTATIONINFO* nNot1=(NOTATIONINFO*) lParam1;
 	NOTATIONINFO* nNot2=(NOTATIONINFO*) lParam2;
return  _tcscmp(nNot1->szEvent,nNot2->szEvent);
}

NotationInfo = new ArrayVector<NOTATIONINFO> (500);

NOTATIONINFO notTemp={0}< 

NotationInfo->Add(notTemp)

...
NOTATIONINFO notTemp = {0};
...
TCHAR szEventToSet[30] = {0};
// Fill here the variable szEventToSet unique out
...
_tcscpy_s(notTemp.szEvent, _countof(notTemp.szEvent), szEventToSet);
NotationInfo->Add(notTemp);
...

for (int i = 0; i < Nnots; i++)
	{
		if (!(*m_NotHeader)[i]->Time)
		{
			continue;
		}

		char szEpoch[20] = {0};
		char szTime[20] = {0};

		char szEvent[NOT_STRING_LENGTH] = {0};
		long	sec_on_this_day = (*m_NotHeader)[i]->Time % 86400;
		int	tm_hour = sec_on_this_day / 3600;
		int	tm_min = (sec_on_this_day / 60) % 60;
		int	tm_sec = sec_on_this_day % 60;

		//[fix355] add feature: include epoch number in Notations list
		LONG lEpoch = (*m_NotHeader)[i]->Time;
		::SendMessage(m_hReviewWnd, TWM_WEEG_MESSAGE, TWGM_WEEG_GETEPOCHFORTIME, (LPARAM) &lEpoch);

		wsprintf(szEpoch, "%ld", lEpoch);
		wsprintf(szTime, "%02d:%02d:%02d.%02d", tm_hour, tm_min, tm_sec, ((*m_NotHeader)[i]->Fractional * 100 / nfh.Fraction_Second_Reference));

		//	Don't try to parenthesize string if RT notation:
		int	flagsToUse = flags;
		if (m_dwStaticEndTime)
		{
			SampleID NT = { (*m_NotHeader)[i]->Time, (*m_NotHeader)[i]->Fractional };
			if (NT >= ST || m_dwStaticEndTime == MAXDWORD)
			{	//	it will be max in monitor mode.
				flagsToUse ^= NSI_MARK_IF_NOT_IN_FILES;
			}
		}

		szEvent[0] = '\0';
		NotationString(m_hNotation, (*m_NotHeader)[i], szEvent, sizeof(szEvent), flagsToUse);
		int nItemCount = ListView_GetItemCount(hLVWnd);
		LVITEM lvi;
		lvi.mask = LVIF_TEXT;
		lvi.iItem = nItemCount;
		lvi.iSubItem = 0;
		lvi.pszText = szEpoch;
		listItemIndex = ListView_InsertItem(hLVWnd, &lvi);
		NotationList.nEpoch = atoi(szEpoch); 
		if (listItemIndex != LV_ERR)
		{
			ListView_SetItemText(hLVWnd, nItemCount, 1, szTime);
			strcpy(NotationList.szDateTime,szTime);  
			ListView_SetItemText(hLVWnd, nItemCount, 2, szEvent);
			strcpy(NotationList.szEvent,szEvent); 
			// add the pointer to the notation to the item data. Later we can use this to identify which item is
			// selected. We need to do this because the list must be sorted. AAD 3/29/03
			assert((*m_NotHeader)[i]);
			lvi.mask = LVIF_PARAM;
			lvi.lParam = (LPARAM)(*m_NotHeader)[i];
			ListView_SetItem(hLVWnd, &lvi);
			ListView_SetTextColor(hLVWnd,NewColor);
		}
		NotationInfo->Add(NotationList); 
	}

...
if (listItemIndex != LV_ERR) {
  ListView_SetItemText(hLVWnd, nItemCount, 1, szTime);
  strcpy(NotationList.szDateTime,szTime);
  ListView_SetItemText(hLVWnd, nItemCount, 2, szEvent);
  strcpy(NotationList.szEvent,szEvent);
  
  NotationInfo->Add(NotationList);                // data saving in own array
  
  lvi.mask = LVIF_PARAM;
  lvi.lParam = (LPARAM) &NotationInfo->GetTail(); // last data assotiation,
  ListView_SetItem(hLVWnd, &lvi);                 // will be used by sorting
  ListView_SetTextColor(hLVWnd, NewColor);
}
...

// set int iInserted = 0 <- before the loop
...
if (listItemIndex != LV_ERR) {
...
  lvi.mask = LVIF_PARAM;
  lvi.lParam = (LPARAM) &NotationInfo[iInserted++];
...
}
...

case LVN_COLUMNCLICK:
        {
            int iCol = ((LPNMLISTVIEW) lParam)->iSubItem;
                if (0 <= iCol && iCol < 3)
                {
                    g_arOrders[iCol] = !g_arOrders[iCol]; // order reversing,                                              // will be used at comparing
                    ListView_SortItems((GetDlgItem(hDlg,LV_NOTATIONS)), ListViewCompareProc, iCol);
                }

int CALLBACK SelectNotationsDlg::ListViewCompareProc(LPARAM lParam1, LPARAM lParam2, LPARAM lParamSort)
{
	LPLVITEMDATA	lplvid1 = (LPLVITEMDATA) lParam1;
	LPLVITEMDATA	lplvid2 = (LPLVITEMDATA) lParam2;
	int				rc = 0;
	int				second_sort = FALSE;
	char epoch1[100];
	char epoch2[100];

	if (lParamSort & second_sort)
	{
		lParamSort &= ~second_sort;
		second_sort = TRUE;
	}

	switch (lParamSort)												// this is the type of sorting being done
	{
	case 0:														// name
		{
			itoa((*NotationInfo)[lplvid1->ListNumber].nEpoch,epoch1,10);
			itoa((*NotationInfo)[lplvid2->ListNumber].nEpoch,epoch2,10);
			rc = Left_Greater_Than_Right(epoch1,epoch2,
												  20, TRUE);
			break;
		}

	case 1:														// type
		{
			rc = Left_Greater_Than_Right((*NotationInfo)[lplvid1->ListNumber].szDateTime, (*NotationInfo)[lplvid2->ListNumber].szDateTime,
												  max(lstrlen((*NotationInfo)[lplvid1->ListNumber].szDateTime), lstrlen((*NotationInfo)[lplvid2->ListNumber].szDateTime)),
																	  FALSE);
			break;
		}

	case 2:														// time
		{
			// compare HH:MM
			rc = Left_Greater_Than_Right((*NotationInfo)[lplvid1->ListNumber].szEvent ,
												  (*NotationInfo)[lplvid2->ListNumber].szEvent, 6, FALSE);
			break;
		}
	}
	if ((!rc) && (Sort1 != Sort2) && (!second_sort))
	{
		rc = ListViewCompareProc(lParam1, lParam2, (Sort2 | second_sort));
	}

	return (rc * g_arOrders[lParamSort]);
	}

int CALLBACK ListViewCompareProc(LPARAM lParam1,
                                 LPARAM lParam2,
                                 LPARAM lParamSort)
{
  int iResult = 0;
  
  int iClickedCol = int(lParamSort);
  
  if (0 <= iClickedCol && iClickedCol < 3) {
    NOTATIONINFO* nNot1=(NOTATIONINFO*) lParam1;        // item A to be compared
    NOTATIONINFO* nNot2=(NOTATIONINFO*) lParam2;        // with item B
  
    iResult = g_arOrders[iClickedCol] ?
              _tcscmp(nNot1->szEvent, nNot2->szEvent) : // forwards sorting
              _tcscmp(nNot2->szEvent, nNot1->szEvent);  // backwards sorting
  }
  
  return iResult;
}