Want to protect your cyber security and still get fast solutions? Ask a secure question today.Go Premium

x
  • Status: Solved
  • Priority: Medium
  • Security: Public
  • Views: 249
  • Last Modified:

Dynamically changing ListBox contents

I have a SORTED List Box and I wish to maintain the currently highlighted selection when strings are added to or taken  away from the total list by events that are external to this subroutine

What happens in my sorted listbox is, if I have say:

string 0 = AAAA
string 1 = CCCC
string 2 = DDDD

and string CCCC is currently highlighted and I save it's index  (icaret = 1)
and a new entry comes along, this time round that is BBBB
so the saved index is out by 1, in other words when I finally do LB_SETCURSEL it highlights BBBB instead of CCCC

so do I have to do a string compare on the new entry/s (it can be multiple entries or deletions) and adjust the saved index on whether the new string/s are inserted or deleted before or after the highlighted string, or is there a simpler way to do this ????????????

// Code snippet of how the listbox gets updated

int icaret; j, iCount;
char szString [19]; // 20 possible listbox entries

// Get current selection index
icaret = SendDlgItemMessage(hdlg,
IDC_USER_LIST,
LB_GETCARETINDEX,
0,
0);

// Clear Listbox for new update
SendDlgItemMessage(hdlg,
IDC_USER_LIST,
LB_RESETCONTENT,
0,
0);
      
// There is an ORDERED array of strings that get entries  added to or subtracted from triggered by external events
// The current count of strings is iCount and varies from time to time

for(j = 0; j < iCount; j++) {
SendDlgItemMessage(hdlg,
IDC_USER_LIST,
LB_ADDSTRING,
(WPARAM) 0,
(LPARAM) szString[j]);
}

// Reset current selection highlight
SendDlgItemMessage(hdlg,
IDC_USER_LIST,
LB_SETCURSEL,
icaret,
(LPARAM) 0);
0
putu
Asked:
putu
  • 4
  • 3
1 Solution
 
putuAuthor Commented:
// Get current selection index
icaret = SendDlgItemMessage(hdlg,
IDC_USER_LIST,
LB_GETCARETINDEX,
0,
0);

//  Probably should be
 
// Get current selection index
icaret = SendDlgItemMessage(hdlg,
IDC_USER_LIST,
LB_GETCURSEL,
0,
0);
0
 
migelCommented:
Hi!
I see two way to solve
1.
You can add a order data to the ListBox item (By LB_SETITEMDATA message)
befor Adding new srtring you can get order data from the currently selected item and after adding you can loop through all items and find order data and select corresponding item.
2. AddString return an index of the inserted element. You can compare it with the saved (selected item before adding) one and set selection depends on the comparation. That is:
 if( nAddedIndex > nSaved)
  nSelIndex = nSaved
else
 nSelIndex = nSaved+1;
0
 
putuAuthor Commented:
migel

I like both of your suggestions and see the concepts.

can you give me some demonstration code ??

I have increased the points and will gladly give you excellent credits if you can.

thanks,
putu

0
Keep up with what's happening at Experts Exchange!

Sign up to receive Decoded, a new monthly digest with product updates, feature release info, continuing education opportunities, and more.

 
putuAuthor Commented:
Re: solution 2 Addstring, what if an item is removed before (sort wise) from the selected item, so effectively it's index becomes 1 less and the highlight will be the one after the actual item ??

I like solution 1 where i can associate a unique identifier with the selected item and search for it

what do you think??


0
 
migelCommented:
Ok!
Way 1.)
//step 1 adding string to the listbox
UINT uListIndex - 0;
for(j = 0; j < iCount; j++)
{
uListIndex =
   SendDlgItemMessage(hdlg,     IDC_USER_LIST,     LB_ADDSTRING,    (WPARAM) 0,
    (LPARAM) szString[j]);
   SendDlgItemMessage(hdlg,     IDC_USER_LIST,     LB_SETITEMDATA,   uListIndex, j);
    }

//Step 2...adding extra data
UINT uLastIndex =    SendDlgItemMessage(hdlg,     IDC_USER_LIST,     LB_GETCOUNT,    0, 0);
UINT uCurSel = SendDlgItemMessage(hdlg,     IDC_USER_LIST,     LB_GETCURSEL,    0, 0);
uCurSel = (UINT)SendDlgItemMessage(hdlg,     IDC_USER_LIST,     LB_GETITEMDATA,    uCurSel, 0);
uListIndex =
   SendDlgItemMessage(hdlg,     IDC_USER_LIST,     LB_ADDSTRING,    (WPARAM) 0,
    (LPARAM) strToAdd);
   SendDlgItemMessage(hdlg,     IDC_USER_LIST,     LB_SETITEMDATA,   uListIndex, uLastIndex);
//Step 3 change selection
for (i = 0; i < uLastIndex+1; i++)
{
if (uCurSel == (UINT)SendDlgItemMessage(hdlg,     IDC_USER_LIST,     LB_GETITEMDATA,    i, 0))
{
SendDlgItemMessage(hdlg,     IDC_USER_LIST,     LB_SETCURSEL,    i, 0);
break;
}
}

Way 2.)
// Step 1 is same ...
// Step 2
UINT uCurSel = SendDlgItemMessage(hdlg,     IDC_USER_LIST,     LB_GETCURSEL,    0, 0);
uListIndex =
   SendDlgItemMessage(hdlg,     IDC_USER_LIST,     LB_ADDSTRING,    (WPARAM) 0,
    (LPARAM) strToAdd);
// step 3.
if (uListIndex <= uCurSel)
 uCurSel++;
SendDlgItemMessage(hdlg,     IDC_USER_LIST,     LB_SETCURSEL, uCurSel, 0);

0
 
putuAuthor Commented:
Excellent answer migel, so can you make your comment added the answer and I will award you the points,
thanks,
putu
0
 
migelCommented:
Good luck!
0

Featured Post

Free Tool: Path Explorer

An intuitive utility to help find the CSS path to UI elements on a webpage. These paths are used frequently in a variety of front-end development and QA automation tasks.

One of a set of tools we're offering as a way of saying thank you for being a part of the community.

  • 4
  • 3
Tackle projects and never again get stuck behind a technical roadblock.
Join Now