C++ Dynamic Tool Tips - c++

Question

We are trying to create dynamic tool tips where the tool tip changes based on the language the user selected. (C++ win api 64 bit application, no external libraries being used)
However we can't get this to work. The tool tip only ever displays the first letter of the text.
Code snipet:
wchar_t* ws = new wchar_t[200];
swprintf(ws, 200, L"Hello");
TTTOOLINFOW toolInfoW = { 0 };
toolInfoW.cbSize = sizeof(toolInfoW);
toolInfoW.hwnd = hDlg;
toolInfoW.uFlags = TTF_IDISHWND | TTF_SUBCLASS;
toolInfoW.uId = (UINT_PTR)hwndTool;
toolInfoW.lpszText = ws;
Even if we hard code the 'Hello', only the first letter is displayed
TTTOOLINFOW toolInfoW = { 0 };
toolInfoW.cbSize = sizeof(toolInfoW);
toolInfoW.hwnd = hDlg;
toolInfoW.uFlags = TTF_IDISHWND | TTF_SUBCLASS;
toolInfoW.uId = (UINT_PTR)hwndTool;
toolInfoW.lpszText = L"Hello";
We must be missing something extremely obvious because it can't be this hard to get this to work.
Thanks in advance for any advice.

Answer 1

Out of curiosity, I've tried it out, and the following code did work when compiled for x64 using MSVC 2019 on Windows 10. It creates a simple window with a button in it, and when you hover over that button, it displays a tooltip with text This works! ☺ (containing a smiley face Unicode character).
Be sure to compile this example with C++17 enabled, otherwise the buffer returned by data() will have type const wchar_t* and thus will be incompatible with the lpszText (member of the TTTOOLINFOW structure), which has type LPWSTR, i.e. just wchar_t*.
#pragma comment(linker, "\"/manifestdependency:type='win32' \
name='Microsoft.Windows.Common-Controls' version='6.0.0.0' \
processorArchitecture='*' publicKeyToken='6595b64144ccf1df' \
language='*'\"")
#pragma comment(lib, "comctl32.lib")
#define _WIN32_WINNT _WIN32_WINNT_WIN10
#ifndef UNICODE
#define UNICODE
#endif
#ifndef _UNICODE
#define _UNICODE
#endif
#include <SDKDDKVer.h>
#include <windows.h>
#include <commctrl.h>
#include <string>
HINSTANCE g_hInstance{ nullptr };
HWND CreateMyButton(HINSTANCE hInstance, HWND hWndApp)
{
return ::CreateWindowExW(0UL, L"BUTTON", L"Hover over this button",
WS_VISIBLE | WS_CHILD | BS_DEFPUSHBUTTON, 45, 10, 200, 35,
hWndApp, nullptr, hInstance, nullptr);
}
void CreateMyTooltip(HWND hWndParent, HWND hWndControl)
{
HWND hWndTip{ ::CreateWindowExW(WS_EX_TOPMOST, TOOLTIPS_CLASSW,
nullptr, WS_POPUP | TTS_NOPREFIX | TTS_ALWAYSTIP, 0, 0, 0, 0,
hWndParent, nullptr, nullptr, nullptr) };
::SetWindowPos(hWndTip, HWND_TOPMOST, 0, 0, 0, 0,
SWP_NOMOVE | SWP_NOSIZE | SWP_NOACTIVATE);
std::wstring wsTooltipText{ L"This works! \u263A" };
TTTOOLINFOW ti{};
ti.cbSize = sizeof ti;
ti.uFlags = TTF_IDISHWND | TTF_SUBCLASS;
ti.hwnd = hWndParent;
ti.uId = reinterpret_cast<UINT_PTR>(hWndControl);
ti.lpszText = wsTooltipText.data();
::SendMessageW(hWndTip, TTM_ADDTOOL, 0U, reinterpret_cast<LPARAM>(&ti));
}
LRESULT CALLBACK MyWndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
switch (msg)
{
case WM_CREATE:
CreateMyTooltip(hWnd, CreateMyButton(g_hInstance, hWnd));
break;
case WM_DESTROY:
::PostQuitMessage(0);
break;
default:
break;
}
return ::DefWindowProcW(hWnd, msg, wParam, lParam);
}
int WINAPI wWinMain(_In_ HINSTANCE hInstance,
_In_opt_ HINSTANCE, _In_ LPWSTR, _In_ int)
{
g_hInstance = hInstance;
const INITCOMMONCONTROLSEX initControls
{
sizeof(INITCOMMONCONTROLSEX),
ICC_STANDARD_CLASSES | ICC_WIN95_CLASSES
};
::InitCommonControlsEx(&initControls);
WNDCLASSW wc{};
wc.lpfnWndProc = MyWndProc;
wc.hInstance = hInstance;
wc.hCursor = ::LoadCursorW(nullptr, IDC_ARROW);
wc.hbrBackground = ::GetSysColorBrush(COLOR_3DFACE);
wc.lpszClassName = L"Tooltip";
::RegisterClassW(&wc);
::CreateWindowExW(0UL, wc.lpszClassName, L"Tooltip Example",
WS_OVERLAPPEDWINDOW | WS_VISIBLE, CW_USEDEFAULT, CW_USEDEFAULT,
300, 100, nullptr, nullptr, hInstance, nullptr);
MSG msg{};
while (::GetMessageW(&msg, nullptr, 0U, 0U))
{
::TranslateMessage(&msg);
::DispatchMessageW(&msg);
}
return static_cast<int>(msg.wParam);
}