MFC 窗口工具栏创建失败，没有错误消息

Question

I am trying to dynamically create a toolbar for my MFC application. I have to following approach for this task. However, the toolbar doesn't show up in my window and I get no error message...

int CMainFrame::OnCreate(LPCREATESTRUCT lpCreateStruct) {
  // ...
  CToolBar menubar;
  if(!menubar.CreateEx(this, TBSTYLE_FLAT | TBSTYLE_LIST, WS_CHILD | WS_VISIBLE | CBRS_TOP | CBRS_FLYBY | CBRS_SIZE_DYNAMIC)) {
    return -1;
  }

  TBBUTTON buttons[5] = {
    { -1, ID_TOOLBAR_FILE, TBSTATE_ENABLED, BTNS_AUTOSIZE | BTNS_DROPDOWN, { 0 }, 0, (INT_PTR)L"File" },
    { -1, ID_TOOLBAR_EDIT, TBSTATE_ENABLED, BTNS_AUTOSIZE | BTNS_DROPDOWN, { 0 }, 0, (INT_PTR)L"Edit" },
    { -1, ID_TOOLBAR_VIEW, TBSTATE_ENABLED, BTNS_AUTOSIZE | BTNS_DROPDOWN, { 0 }, 0, (INT_PTR)L"View" },
    { -1, ID_TOOLBAR_LAYOUT, TBSTATE_ENABLED, BTNS_AUTOSIZE | BTNS_DROPDOWN, { 0 }, 0, (INT_PTR)L"Layout" },
    { -1, ID_TOOLBAR_HELP, TBSTATE_ENABLED, BTNS_AUTOSIZE | BTNS_DROPDOWN, { 0 }, 0, (INT_PTR)L"Help" }
  };


  ::SendMessage(menubar.GetSafeHwnd(), TB_BUTTONSTRUCTSIZE, (WPARAM)sizeof(TBBUTTON), 0);
  ::SendMessage(menubar.GetSafeHwnd(), TB_ADDBUTTONS, (WPARAM)5, (LPARAM)&buttons);

  ::SendMessage(menubar.GetSafeHwnd(), TB_AUTOSIZE, 0, 0);
  ::ShowWindow(menubar.GetSafeHwnd(), SW_SHOW);
}

This will not display my toolbar. Why is this happening?

Answer 1

I found out that declaring the toolbar as class member solves the problem. So here is what I did:

class CMainFrame : public CFramWnd {
protected:
  CToolBar m_wndToolBar;
  // ...
}

And the rest of the code is practically unchanged. I am still not sure why it works this way.