Very simple example with Listbox in winapi

Question

How can I display in MessageBox text selected in ListBox? I try to use next code, but it display only blank MessageBox

wchar_t listBoxStr[15];
HWND hWndList;

switch (message)
{
case WM_CREATE:
    hWndList = CreateWindowEx(WS_EX_CLIENTEDGE, TEXT("listbox"), "", WS_CHILD | WS_VISIBLE | WS_VSCROLL | ES_AUTOVSCROLL, 240, 40, 150, 20, hwnd, (HMENU)105, NULL, NULL);
    SendMessage(hWndList, LB_ADDSTRING, 0, (LPARAM)"name");
    SendMessage(hWndList, LB_ADDSTRING, 0, (LPARAM)"extension");
    SendMessage(hWndList, LB_ADDSTRING, 0, (LPARAM)"date");
    SendMessage(hWndList, LB_ADDSTRING, 0, (LPARAM)"size");
    CreateWindowEx(NULL, TEXT("button"), TEXT("FIND"), WS_VISIBLE | WS_CHILD, 410, 40, 50, 20, hwnd, (HMENU)106, NULL, NULL);
    return 0 ;
    return 0 ;
case WM_COMMAND:
    switch(LOWORD(wParam))
    {
    case 106:
        SendMessageW(hWndList, LB_GETTEXT,0,(LPARAM)listBoxStr);
        MessageBoxW(NULL, listBoxStr, L"", NULL);
        return 0;
    }
    return 0;
case WM_PAINT:
    hdc = BeginPaint (hwnd, &ps);
    GetClientRect (hwnd, &rect) ;
    EndPaint (hwnd, &ps) ;
    return 0 ;
case WM_DESTROY:
    PostQuitMessage (0) ;
    return 0 ;
}

Solution 1

The 1st parameter of SendMessage should be the listbox handle, not the parent window handle.

Solution 2

Make hWndList static by defining

static HWND hWndList;

Then try like this

 -  SendMessage(hWndList, LB_ADDSTRING, 0, (LPARAM) L"name");
 -  SendMessage(hWndList, LB_ADDSTRING, 0, (LPARAM) L"extension");
 -  SendMessage(hWndList, LB_ADDSTRING, 0, (LPARAM) L"date");
 -  SendMessage(hWndList, LB_ADDSTRING, 0, (LPARAM) L"size");

Comments

[abilash]

I don't know why but in that case I've got an error "Variable hWndList is being used without is being initialized", but I've initialized it in WM_Create. Doesn't it? Look edition of qestion.

[Andrey]

@Vsevywniy: it should be a member variable

[abilash]

In that way it also return first item text value. I need selected one.

[Andrey]

@Vsevywniy: See the answer to stackoverflow.com/questions/739095/…