ListView Sorting - CompareFunction

Hi...
I would liekt to sor the listview according to column which was pressed.
Everything is OK until the
CompareFun(LPARAM lParam1,LPARAM lParam2,LPARAM sortParm)
is hit. Neither of the LPARAM 1 or 2 pass what they suposed to. They pass a value of 0 for both and sortParam
passes the column which was pressed. Below is my source.

ItemStruct *pItem1    = (ItemStruct*) lParam1;
ItemStruct *pItem2    = (ItemStruct*) lParam2;
After this assignment is done both of these are NULL
ie: pItem1 , pItem2.

Can someone take a look and tell me what is wrong.

Thank you in Advance.
Kind Regards Paul
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typedef struct
{
  int nItemNo;
  char strName[110];
}ItemStruct;

int CALLBACK CompareFunc(LPARAM lParam1, LPARAM lParam2, LPARAM lParamSort)
{
  int result;
  ItemStruct *pItem1    = (ItemStruct*) lParam1;
  ItemStruct *pItem2    = (ItemStruct*) lParam2;
  if(pItem1 ==  NULL || pItem2 == NULL)
     return 0;
  switch(lParamSort)
  {
    case 0:
      if(pItem1->nItemNo < pItem2->nItemNo)
         result = -1;
      else
      if(pItem1->nItemNo == pItem2->nItemNo)
         result = 0;
      else
         result = 1;
      break;

      case 1:
        result = strcmp(pItem1->strName,pItem2->strName);
        break;

      default:
        result = 0;
        break;
  }
  return result;
}

void OnColumnclickList1(HWND hWnd,LPARAM lParam)
{
    HWND lWnd;
    int nColumn;
    NM_LISTVIEW* pNMListView = (NM_LISTVIEW*)lParam;
     lWnd = GetDlgItem(hWnd,ID_SEARCHLIST);
    nColumn = pNMListView->iSubItem;
    ListView_SortItems(lWnd,CompareFunc,nColumn);
}

LRESULT SListViewNotify(HWND hWnd,LPARAM lParam)
{
   LPNMHDR  lpnmh = (LPNMHDR) lParam;
   if(search_set == 0)
      return 0;
   switch(lpnmh->code)
   {
      case LVN_COLUMNCLICK:
         OnColumnclickList1(hWnd,lParam);
         break;
   }
   return 0;
}

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