In writing your tool tip notification handler, you need to use the TOOLTIPTEXT structure. The members of the TOOLTIPTEXT structure are:

typedef struct {
    NMHDR     hdr;        // required for all WM_NOTIFY messages
    LPTSTR    lpszText;   // see below
    TCHAR     szText[80]; // buffer for tool tip text
    HINSTANCE hinst;      // see below
    UINT      uflags;     // flag indicating how to interpret the
                          // idFrom member of the NMHDR structure
                          // that is included in the structure

Identifies the tool that needs text. The only member of this structure you might need is the control's command ID. The control's command ID will be in the idFrom member of the NMHDR structure, accessed with the syntax hdr.idFrom. See NMHDR for a discussion of members of the NMHDR structure.

Address of a string to receive the text for a tool.

Buffer that receives the tool tip text. An application can copy the text to this buffer as an alternative to specifying a string address.

Handle of the instance that contains a string to be used as the tool tip text. If lpszText is the address of the tool tip text, this member is NULL.

When you handle the TTN_NEEDTEXT notification message, specify the string to be displayed in one of the following ways:

  • Copy the text to the buffer specified by the szText member.

  • Copy the address of the buffer that contains the text to the lpszText member.

  • Copy the identifier of a string resource to the lpszText member, and copy the handle of the instance that contains the resource to the hinst member.

See also

Tool Tips in Windows Not Derived from CFrameWnd