Solved

ListView Sorting - CompareFunction

Posted on 2001-07-26
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703 Views
Last Modified: 2013-12-03
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
---------------------------------------------------------
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;
}

---------------------------------------------------------
0
Comment
Question by:pawel3
9 Comments
 
LVL 15

Accepted Solution

by:
NickRepin earned 200 total points
ID: 6324782
<<The lParam1 parameter is the 32-bit value associated with the first item being compared, and the lParam2 parameter is the value associated with the second item.>>

You have to explicitely assign a certain value to lParam for each listview item when you create a listview.

By default, lParam contains zero.

lParam is among other members in LVITEM structure.

0
 
LVL 5

Expert Comment

by:robpitt
ID: 6324802
Question:
In your OnColumnclickList1() what is the ID_SEARCHLIST thing all about?


Also be sure to check that your actually setting the lParam correctly in the first place. I.e. check that the LVITEM mask member includes LVIF_PARAM as well as setting the lParam member to your structure address.

Rob
0
 
LVL 5

Expert Comment

by:robpitt
ID: 6326006
PS Ignore my first question about ID_SEARCHLIST - I was just being dim.
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Expert Comment

by:AKRover
ID: 6372658
can u post the code that uses LVM_INSERTITEM?
0
 

Author Comment

by:pawel3
ID: 6681287
thank you NickRepin
you suggestion worked fine
0
 
LVL 15

Expert Comment

by:NickRepin
ID: 6682531
if so then could you accept my comment as an answer?
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