Problem with a listbox on a dialog box!

[abdul]

I have a listbox on a dialog box. I want to change the text of a static control to the selected text of the listbox whenever the selection is changed. The listbox is a "single selection" listbox and it has "LBS_NOTIFY" style. I am using the following code but nothing happens:

case ID_LIST:
if(HIWORD(wparam) == LBN_SELCHANGE)
{
selindex = SendMessage(GetDlgItem(hwnd, ID_LIST),
LB_GETCURSEL,0,0);
sellen = SendMessage(GetDlgItem(hwnd, ID_LIST), LB_GETTEXTLEN,selindex,0);
seltext = (char*)GlobalAlloc(GPTR, sellen + 1);
SendMessage(GetDlgItem(hwnd, ID_LIST), LB_GETTEXT,selindex, (LPARAM)seltext);
SetDlgItemText(hwnd, ID_SELECTION, "seltext");
GlobalFree(seltext);
}

Can you check the error in there please?

[Chris]

you need to capture the LBN_SELCHANGE message under the WM_COMMAND -> HIWORD(wParam) as show below sample code:

LRESULT CALLBACK MyDlg(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam)
{
    int        idx =0, sz=0;
    char    *str;

    switch (message)
    {
    case WM_INITDIALOG:
        return TRUE:
    case WM_PAINT:
        break;
    case WM_COMMAND:
        switch (HIWORD(wParam))
        {
        case LBN_SELCHANGE:
            idx = SendMessage((HWND)lParam, LB_GETCURSEL, 0, 0);
            if (idx != LB_ERR)
            {
                sz = SendMessage((HWND)lParam, LB_GETTEXTLEN, (WPARAM)idx, 0); 
                if (sz > 0)
                {
                    str = new char[sz+1];
                    memset(str, 0, sz+1);
                    SendMessage((HWND)lParam, LB_GETTEXT, idx, (LPARAM)str);
                    SetDlgItemText(hDlg, IDC_EDIT1, str);
                    delete [] str;
                }
            }
            break;
        default:
            break;
    }
    return FALSE;
} 

[abdul]

It does not work at all now. I think there is some problem in the returning value. Can you please find it!

[Technocrat]

Can you post the entire programs code?

[abdul]

Here is my C++ source file:

#include <windows.h>
#include "resource.h"

BOOL CALLBACK MyDlgProc(HWND, UINT, WPARAM, LPARAM);
char *buffer, *seltext;
int x,y,len, sellen, selindex;
HRGN hrgn;
HINSTANCE hinst;
int WINAPI WinMain(HINSTANCE hinstance, HINSTANCE hprevinstance, LPSTR lpcmdline, int nshowcmd)

{
	hinst = hinstance;
	MSG msg;

	DialogBox(hinstance, MAKEINTRESOURCE(MYDLG), NULL, MyDlgProc);

	while(GetMessage(&msg, NULL, 0,0))
	{
		TranslateMessage(&msg);
		DispatchMessage(&msg);
	}

	return msg.wParam;
}


BOOL CALLBACK MyDlgProc(HWND hwnd, UINT msg, WPARAM wparam, LPARAM lparam)
{
	hrgn = CreateEllipticRgn(10,10,330,330);

	switch(msg)
	{
	case WM_INITDIALOG:

		SetWindowRgn(hwnd, hrgn, FALSE);
		return TRUE;
	case WM_SHOWWINDOW:
		SetFocus(GetDlgItem(hwnd, ID_TEXT));
		return TRUE;
	case WM_CLOSE:

		EndDialog(hwnd, NULL);
		PostQuitMessage(0);
		return TRUE;

	case WM_COMMAND:

				switch (HIWORD(wparam))
		{
				case LBN_SELCHANGE:
				selindex = SendMessage(GetDlgItem(hwnd, ID_LIST), LB_GETCURSEL,0,0);
				sellen = SendMessage(GetDlgItem(hwnd, ID_LIST), LB_GETTEXTLEN,selindex,0);
				seltext = (char*)GlobalAlloc(GPTR, sellen + 1);
				SendMessage(GetDlgItem(hwnd, ID_LIST), LB_GETTEXT,selindex, (LPARAM)seltext);
				SetDlgItemText(hwnd, ID_SELECTION, "seltext");
				GlobalFree(seltext);
				break;
				default:
					break;
		}
				break;

		switch(LOWORD(wparam))
		{
		case ID_ADD:
			len = GetWindowTextLength(GetDlgItem(hwnd, ID_TEXT));
			if(len != NULL)
			{
			buffer = (char*)GlobalAlloc(GPTR, len + 1);

			GetDlgItemText(hwnd, ID_TEXT, buffer, len + 1);

			SendMessage(GetDlgItem(hwnd,ID_LIST), LB_ADDSTRING, 0, (LPARAM) buffer);
			SetDlgItemText(hwnd, ID_TEXT, NULL);
			SetFocus(GetDlgItem(hwnd, ID_TEXT));
			
			GlobalFree(buffer);
			}
			return TRUE;
		case ID_CLEAR:
SendMessage(GetDlgItem(hwnd, ID_LIST), LB_RESETCONTENT, 0,0);
return TRUE;
case IDOK:
 EndDialog(hwnd, IDOK);
 PostQuitMessage(0);
 return TRUE;
		}
		break;
	}
	return FALSE;
}

[abdul]

Never mind!
It is working now. I just tried to change the text of another child window (not ID_SELECTION) and it works fine.

[Technocrat]

Ok cool. I was going to have to ask you for the resource file because I was having a problem getting mine to work like I am sure it was supposed to.

PS. Nice dialog affect

[abdul]

I also had problem naming the controls and menus. It my "text editor" program, I named my menus like this:

ID_FILE_OPEN
ID_FILE_SAVEAS
ID_FILESAVE


Now I perform certain function when a certain menu is clicked. But it does do any thing when "ID_FILE_OPEN" is clicked. When I changed its name to "ID_OPEN" it worked but and when I change it back to "ID_FILE_OPEN" , it does not work.

The same thing is with the "ID_SELECTION" static control. I can set its text when I change its name to "ID_SEL" but when I change it back to "ID_SELECTION", I cannot change the text.

I dont know if there is problem with the compiler (VC++) or something is rong sometime.

[Technocrat]

Try doing a clean, then rebuild all. See if that cleans up your problem.

[abdul]

I is working now but i got another problem:

When I run my program, and select(set the focus) to the "ID_ADD" (which is default button) -> and then I press any key, it unloads the dialog box. I dont know why its doing that because I have not put any code that unloads the dialog box when "ID_ADD" button is clicked.