Brief Intro
By default, ActiveX controls do not support tooltips. This
article demonstrates how to add tooltip to an ActiveX control.
This control can be used to add tooltips to ActiveX controls
that we develop. Steps Involved: We have used the 'MFC ActiveX
Control Wizard' to develop the 'mytooltip' control. The steps
involved are enumerated below:
(a) Select 'MFC ActiveX Control Wizard' as new
project type with project name as 'mytooltip'. Click on 'OK'. to
let the wizard generate the code.
(b) Open the 'stdafx.h' file associated with the
project and add the following line: #include
<afxcmn.h>
The header file 'afxcmn.h' contains declarations for MFC classes that serve as
wrappers to Windows Common Controls including
CToolTipCtrl. Add the following lines to COleControl-derived class CMytooltipCtrl located in
'mytooltipctl.h': CToolTipCtrl m_ttip; Use ClassWizard
to add an OnCreate( ) handler to the message map. It is
in this routine that the ToolTip control will be created. Add
the following code to this handler:
m_ttip.Create ( this ) ;
m_ttip.AddTool ( this,
LPCTSTR ( m_toolTipText ) ) ;
m_ttip.SetTipBkColor ( RGB (
255,255,0 ) ) ;
m_ttip.SetTipTextColor ( RGB ( 255,0,0 ) ) ;
Alter CMytooltipCtrl::DoPropExchange( ) by
adding code to initialize the m_toolTipText and
m_showToolTip properties:
PX_Bool(pPX, _T("ShowToolTip"), m_showToolTip, FALSE);
PX_String(pPX,
_T("ToolTipText"), m_toolTipText, _T(""));
To allow the user of the control some control over
the ToolTip functionality, use ClassWizard to add the following
Automation properties to the CBasicCtrl class:
External Name: ShowToolTip ToolTipText
Type:
BOOL CString
Variable name: m_showToolTip m_toolTipText
Notification function: OnShowToolTipChanged
OnToolTipTextChanged
ShowToolTip will allow the user to suppress
the display of the tooltip, and ToolTipText will track
the text that is to be displayed when the tooltip is visible. To
make this work we have added a virtual function
PreTranslateMessage( ) to the control class and called
RelayEvent( ) function from it.
|
