Adding Tooltips to Checkboxes in ATL-based C++ Dialogs - c++

Question

I'm attempting to add a set of tooltips to a set of checkboxes on a dialog inheriting from CAxDialogImpl, where CSG32GridViewControlDlg is my dialog's class.
Using the example code on MSDN as a base, I've added the following code:
void CSG32GridViewControlDlg::AddCheckboxTooltip(const int toolId, PTSTR tooltipText)
{
HWND hCheckbox = GetDlgItem(toolId);
char label1[501];
::GetWindowText(hCheckbox, label1, 500);
HINSTANCE hInstance = _AtlBaseModule.GetResourceInstance( ); // This bit I'm not sure about...
// Need to create the ToolTip first
HWND hWndToolTip = ::CreateWindowEx(NULL, TOOLTIPS_CLASS, NULL,
WS_POPUP | TTS_ALWAYSTIP | TTS_BALLOON,
CW_USEDEFAULT, CW_USEDEFAULT,
CW_USEDEFAULT, CW_USEDEFAULT,
hCheckbox,
NULL,
hInstance, 0);
if (!hCheckbox || !hWndToolTip)
{
return;
}
TOOLINFO toolInfo = { 0 };
toolInfo.cbSize = sizeof(toolInfo);
toolInfo.hwnd = hCheckbox;
toolInfo.uFlags = TTF_IDISHWND | TTF_SUBCLASS;
toolInfo.uId = (UINT_PTR)hWndToolTip;
toolInfo.lpszText = tooltipText;
LRESULT result = ::SendMessage(hWndToolTip, TTM_ADDTOOL, 0, (LPARAM) &toolInfo);
return hWndToolTip;
}
Debugging the code, I can see that the message gets sent, and the result comes back as "1", which would seem to suggest that everything's worked successfully. But when I mouseover the checkbox in question... no tooltip.
What could I do to check if the tooltip is successfully registered, and why might it not be appearing on Mouseover? Alternatively, is there a better way to approach this?

Answer 1

There are a few problems with your code. The starting point worth mentioning is obviosuly this: How to Create a Tooltip for a Control.
Parent window for the tooltip control should be the dialog, not the checkbox
uId member for the tool with TTF_IDISHWND flag needs to be the tool window, and not tooltip control window
This gives code:
HWND AddCheckboxTooltip(const int toolId, PTSTR tooltipText)
{
HWND hCheckbox = GetDlgItem(toolId);
// Need to create the ToolTip first
HWND hWndToolTip = ::CreateWindowEx(NULL, TOOLTIPS_CLASS, NULL,
WS_POPUP | TTS_ALWAYSTIP | TTS_BALLOON,
CW_USEDEFAULT, CW_USEDEFAULT,
CW_USEDEFAULT, CW_USEDEFAULT,
m_hWnd,
NULL,
_AtlBaseModule.GetModuleInstance(), 0);
if (!hCheckbox || !hWndToolTip)
return NULL;
TOOLINFO toolInfo = { 0 };
toolInfo.cbSize = sizeof(toolInfo);
toolInfo.hwnd = hCheckbox;
toolInfo.uFlags = TTF_IDISHWND | TTF_SUBCLASS;
toolInfo.uId = (UINT_PTR)hCheckbox;
toolInfo.lpszText = tooltipText;
LRESULT result = ::SendMessage(hWndToolTip, TTM_ADDTOOL,
0, (LPARAM) &toolInfo);
return hWndToolTip;
}
LRESULT OnInitDialog(UINT, WPARAM, LPARAM, BOOL& /*bHandled*/)
{
AddCheckboxTooltip(IDC_CHECK1, _T("Checkbox Tooltip Test"));
//...
Which runs as: