Tool Tips in Windows Not Derived from CFrameWnd
This article family covers enabling tool tips for controls contained in a window that is not derived from CFrameWnd. The article Toolbars Tool Tips provides information about tool tips for controls in a CFrameWnd.
Topics covered in this article family include:
Tool tips are automatically displayed for buttons and other controls contained in a parent window derived from CFrameWnd. This is because CFrameWnd has a default handler for the TTN_GETDISPINFO notification, which handles TTN_NEEDTEXT notifications from tool tip controls associated with controls.
However, this default handler is not called when the TTN_NEEDTEXT notification is sent from a tool tip control associated with a control in a window that is not a CFrameWnd, such as a control on a dialog box or a form view. Therefore, it is necessary for you to provide a handler function for the TTN_NEEDTEXT notification message in order to display tool tips for child controls.
The default tool tips provided for your windows by CWnd::EnableToolTips do not have text associated with them. To retrieve text for the tool tip to display, the TTN_NEEDTEXT notification is sent to the tool tip control's parent window just before the tool tip window is displayed. If there is no handler for this message to assign some value to the pszText member of the TOOLTIPTEXT structure, there will be no text displayed for the tool tip.