ListBox Question

This is the code I have for my Dialog Box:

Code:

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INT_PTR CALLBACK DlgMng(HWND hWndDlg, UINT Message, WPARAM wParam, LPARAM lParam) {
    switch(Message) {
          case WM_INITDIALOG: {
              TCITEM tci;
              tci.mask = TCIF_TEXT;
              tci.pszText = "Tab 1";
              tci.iImage = -1;
              TabCtrl_InsertItem(GetDlgItem(hWndDlg,ID_TAB), 0, &tci);
              tci.pszText = "Tab 2";
              TabCtrl_InsertItem(GetDlgItem(hWndDlg,ID_TAB), 1, &tci);
              pane2=true;
              NMHDR nmh;
              nmh.hwndFrom = hWndDlg;
              nmh.idFrom = ID_TAB;
              nmh.code = TCN_SELCHANGE;
              TabCtrl_SetCurSel(GetDlgItem(hWndDlg,ID_TAB),0);
              SendMessage(hWndDlg,WM_NOTIFY,nmh.idFrom,(LPARAM)&nmh);
              return true;
          }
          case WM_NOTIFY:
              if(((LPNMHDR)lParam)->code==TCN_SELCHANGE) {
                    if(pane2) {
                        SetWindowPos(GetDlgItem(hWndDlg,ID_LIST),NULL,0,0,0,0,SWP_NOZORDER);
                        SetWindowPos(GetDlgItem(hWndDlg,IDOK),NULL,122,331,45,26,SWP_NOZORDER);
                        SetWindowPos(GetDlgItem(hWndDlg,IDCANCEL),NULL,182,331,45,26,SWP_NOZORDER);
                    } else {
                        SendDlgItemMessage(hWndDlg,ID_LIST,LB_RESETCONTENT,0,0);
                        SetWindowPos(GetDlgItem(hWndDlg,ID_LIST),NULL,15,37,319,300,SWP_NOZORDER);
                        SetWindowPos(GetDlgItem(hWndDlg,IDOK),NULL,122,331,45,26,SWP_NOZORDER);
                        SetWindowPos(GetDlgItem(hWndDlg,IDCANCEL),NULL,182,331,45,26,SWP_NOZORDER);
                        if(mysql_query(database,"SELECT `id`,`text` FROM `table`")) {
                              my_error(hWndDlg,true,140,0,mysql_error(database));
                              return false;
                        }
                        result = mysql_store_result(database);
                        for(int a=0;a<mysql_num_rows(result);a++) {
                              row = mysql_fetch_row(result);
                              SendMessage(GetDlgItem(hWndDlg,ID_LIST),LB_ADDSTRING,0,(LPARAM)row[1]);
                              SendMessage(GetDlgItem(hWndDlg,ID_LIST),LB_SETITEMDATA,a,(LPARAM)row[0]);
                        }
                    }
                    pane2=!pane2;
              }
              return true;
          case WM_COMMAND:
              switch(LOWORD(wParam)) {
                    case IDCANCEL:
                        EndDialog(hWndDlg,0);
                        break;
                    case IDOK:
                        MessageBox(0,editid.c_str(),editid.c_str(),0);
                        break;
                    case ID_LIST:
                        switch(HIWORD(wParam)) {
                              case LBN_SELCHANGE: {
                                  int list = SendMessage(GetDlgItem(hWndDlg,ID_LIST),LB_GETCURSEL,0,0);
                                  int data = SendMessage(GetDlgItem(hWndDlg,ID_LIST),LB_GETITEMDATA,list,0);
                                  std::stringstream str;
                                  str << data;
                                  editid = (string)"a"+str.str();
                                  break;
                              }
                        }
                        break;
              }
              return true;
          case WM_LBUTTONDOWN:
              SendMessage(hWndDlg, WM_NCLBUTTONDOWN, HTCAPTION, lParam);
              return true;
          default:
              return false;
    }
}

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Some variables are defined before this function...Anyway, the "data" variable contains 0 no matter what the id of the mysql row is. My question is, what am I doing incorrectly?

Thanks for any help, it is much appreciated.

Code:

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SendMessage(GetDlgItem(hWndDlg,ID_LIST), LB_ADDSTRING, 0, (LPARAM)row[1]);
SendMessage(GetDlgItem(hWndDlg,ID_LIST), LB_SETITEMDATA, a, (LPARAM)row[0]);

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Where does the value in the variable 'a' come from? It seems that you should be using the return value of LB_ADDSTRING here.

for(int a=0;a<mysql_num_rows(result);a++) {

Thats where 'a' comes from. I've tried using:

int x = SendMessage(GetDlgItem(hWndDlg,ID_LIST), LB_ADDSTRING, 0, (LPARAM)row[1]);

And then I would use the 'x' variable in place of the 'a' variable, but that didnt work either.

Have you checked the return value from SendMessage to ensure it's a valid, non LB_ERR value when you send either the LB_ADDSTRING or LB_SETITEMDATA messages?

I tried this:

int x = SendMessage(...LB_ADDSTRING...);
int y = SendMessage(...LB_SETITEMDATA,x....);
if(x==LB_ERR | y==LB_ERR) MessageBox(0,"Error","Error",0);

And I didnt get the MessageBox error. Any other suggestions? Thanks for your suggestions so far.

How stupid can I be? I'm SET(ting)ITEMDATA as a char* variable and GET(ting)ITEMDATA as a int variable. row[0] may contain only integers, but a mysql row is a char* no matter what. I just need to return the data into the data variable like this:

string data = (const char*)SendMessage(...LB_GETITEMDATA...);

Once I did that, it worked. Then I was able to note that I needed to use:

int x = SendMessage(...LB_ADDSTRING);
SendMessage(...LB_SETITEMDATA,x...);

to correctly return the right values. I hope this helps someone besides myself.