When you specify the TBSTYLE_TOOLTIPS style, the toolbar creates and manages a tool tip control. A tool tip is a small pop-up window that contains a line of text describing a toolbar button. The tool tip is hidden, appearing only when the user puts the cursor on a toolbar button and leaves it there for approximately one-half second. The tool tip is displayed near the cursor.
Before the tool tip is displayed, the TTN_NEEDTEXT notification message is sent to the toolbar’s owner window to retrieve the descriptive text for the button. If the toolbar's owner window is a CFrameWnd window, tool tips are displayed wihout any extra effort, because CFrameWnd has a default handler for the TTN_NEEDTEXT notification. If the toolbar’s owner window is not derived from CFrameWnd, such as a dialog box or form view, you must add an entry to your owner window's message map and provide a notification handler in the message map. The entry to your owner window’s message map is as follows:
ON_NOTIFY_EX( TTN_NEEDTEXT, 0, memberFxn )
memberFxn
The member function to be called when text is needed for this button.
Note that the id of a tool tip is always 0.
In addition to the TTN_NEEDTEXT notification, a tool tip control can send the following notifications to a toolbar control:
| Notification | Meaning |
| TTN_NEEDTEXTA | Tool tip control requires ASCII text (Win95 only) |
| TTN_NEEDTEXTW | Tool tip control requires UNICODE text (Windows NT only) |
| TBN_HOTITEMCHANGE | Indicates that the hot (highlighted) item has changed. |
| NM_RCLICK | Indicates the user has right-clicked a button. |
| TBN_DRAGOUT | Indicates the user has clicked the button and dragged the pointer off the button. It allows an application to implement drag and drop from a toolbar button. When receiving this notification, the application will begin the drag and drop operation. |
| TBN_DROPDOWN | Indicates the user has clicked a button that uses the TBSTYLE_DROPDOWN style. |
| TBN_GETOBJECT | Indicates the user moved the pointer over a button ithat uses the TBSTYLE_DROPPABLE style. The message. |
For an example handler function and more information about enabling tool tips, see Tool Tips in Visual C++ Programmer’s Guide.