Subclassing SHBrowseForFolder and handling WM_NOTIFY

Question

I'm trying to fix SHBrowseForFolder dialog, as it doesn't react on folder renaming (BFFM_SELCHANGED isn't being sent and there is no way to determine is the path now correct or not). I googled a solution, which said like I have to subclass dlg's wndproc and catch TVN_ENDLABELEDIT to send BFFM_SELCHANGED myself.

Here is how I set new wndproc when I get BFFM_INITIALIZED:

for (HWND hChild = GetWindow(hWnd, GW_CHILD); hChild != 0; hChild = GetWindow(hChild, GW_HWNDNEXT)) {
    szClassName[256];
    GetClassName(hChild, szClassName, sizeof(szClassName));
    if (!stricmp(szClassName, "SHBROWSEFORFOLDER SHELLNAMESPACE CONTROL")) {
        oldWndProc = reinterpret_cast<WNDPROC>(SetWindowLongPtr(hChild, GWLP_WNDPROC, reinterpret_cast<LONG_PTR>(_SubclassWndProc)));
        break;
    }
}

Here is _SubclassWndProc:

static LRESULT _SubclassWndProc(HWND hWnd, UINT uMsg, WPARAM lParam, LPARAM lpData) {
  switch (uMsg) {
     case WM_NOTIFY:
        switch (((LPNMHDR)lParam)->code) {
           case TVN_ENDLABELEDIT:
              break;
        }
        break;
  }
  return CallWindowProc(oldWndProc, hWnd, uMsg, lParam, lpData);
}

It works only if I comment WM_NOTIFY block. Even an access to lParam breaks dialog (it contains corrupted treee with empty labels). If I call oldWndProc before switch, then it works, but in WM_NOTIFY case lParam obviously doesn't contain a pointer to NMHDR, it contains a small integer value like 1,2,100 etc.

Edit: The question can be shortened to "Why does WM_NOTIFY come without a pointer to NMHDR?"

Answer 1

The error was due to my negligence: I copied wndproc signature from some example, which has agrument names confused. The lParam usually comes last and has a type LPARAM. So I was trying to cast arg usually called wParam, which contains a control id not LPNMHDR.