Knowledge Base

How to add tooltips to ATL ActiveX controls

Article ID: 201540

Article Last Modified on 4/29/2005

APPLIES TO

This article was previously published under Q201540

SUMMARY

By default, ATL ActiveX controls do not support tooltips. Some containers like Microsoft Visual Basic add the tooltips as an extended control property (ToolTipText) for the ActiveX control. However, not all containers have this feature. If you want to support tooltips in several containers, you need to add tooltip support to your ATL ActiveX control yourself. This article shows how to add tooltip support to an ATL ActiveX Control.

Here are three ways to add tooltip support to an ATL ActiveX control.
  • Use tooltip windows common control.
  • Use MFC's CToolTipCtrl class.
  • Use CToolTipCtrl ATL class from ATLCON sample.

MORE INFORMATION

Using tooltip windows common control

  1. Add a variable to your ATL control class of type CWindow. 
    CWindow m_wndToolTip;
  2. Include Commctrl.h in Stdafx.h file.(include Afxcmn.h if application has MFC support). 
    #include <commctrl.h>
  3. Override InplaceActive method and add the following code to create tooltip control.
    	
HRESULT InPlaceActivate(LONG iVerb, const RECT* prcPosRect=NULL)
{
	HRESULT hr;

	hr = CComControlBase::InPlaceActivate(iVerb, prcPosRect);
	if (m_wndToolTip.m_hWnd == NULL)
	{
		// If we're windowless we still need an HWND 
		if (m_bWndLess)
		{
			HDC hDC;
			// Get the HDC from the client
			m_spInPlaceSite->GetDC(NULL, OLEDC_NODRAW, &hDC);
			m_hTheWnd = WindowFromDC(hDC);
			m_spInPlaceSite->ReleaseDC(hDC);
		}
		else
			m_hTheWnd = m_hWnd;

		//Load the Common control library and create tooltip control
		InitCommonControls();
		m_wndToolTip.m_hWnd =
		::CreateWindow(TOOLTIPS_CLASS, (LPTSTR)NULL, TTS_ALWAYSTIP,
			CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT,
			NULL, (HMENU) NULL, _Module.GetModuleInstance(), NULL);

		// Ensure the tooltip always appears above our window
		::SetWindowPos(m_wndToolTip.m_hWnd, HWND_TOPMOST,0,0,0,0,
				SWP_NOACTIVATE|SWP_NOMOVE|SWP_NOREDRAW|SWP_NOSIZE);

		TOOLINFO    ti;
		ti.cbSize = sizeof(TOOLINFO);
		ti.uFlags = 0;
		ti.hwnd   = m_hTheWnd;
		ti.uId    = 1;
		ti.hinst  = NULL;
		ti.lpszText = m_bWndLess ? ti.lpszText = _T("My Windowless Tip") : ti.lpszText = _T("My Windowed Tip");
		m_wndToolTip.SendMessage(TTM_ADDTOOL, 0, (LPARAM)&ti);
	}
	return hr;
}
  4. Create a variable m_hTheWnd of type HWND in control class and then create handlers for WM_LBUTTONDOWN and WM_MOUSEMOVE to the control's class. Relay appropriate messages to the ToolTip control. The sample code is shown in the following:
    	
void RelayEvent(UINT message, WPARAM wParam, LPARAM lParam)
{
	if (NULL != m_wndToolTip.m_hWnd)
	{
		MSG msg;

		msg.hwnd= m_hTheWnd;
		msg.message= message;
		msg.wParam= wParam;
		msg.lParam= lParam;
		msg.time= 0;
		msg.pt.x= LOWORD (lParam);
		msg.pt.y= HIWORD (lParam);

		::SendMessage(m_wndToolTip.m_hWnd, TTM_RELAYEVENT, 0, (LPARAM)&msg);	
	}
} 

LRESULT OnLButtonDown(UINT uMsg, WPARAM wParam, LPARAM lParam,BOOL bHandled)
{
	bHandled = FALSE;
	RelayEvent(uMsg, (WPARAM)wParam,MAKELPARAM(LOWORD(lParam), HIWORD(lParam)));
	return 0L; 
}


LRESULT OnMouseMove(UINT uMsg, WPARAM wParam, LPARAM lParam,BOOL& bHandled)
{
	if (m_wndToolTip.m_hWnd)
	{
		POINT pt;
		static uId;
		pt.x = LOWORD(lParam);
		pt.y = HIWORD(lParam);

		TOOLINFO ti;
		ti.cbSize = sizeof(TOOLINFO);
		ti.hwnd   = m_hTheWnd;
		ti.uId    = 1;
		ti.rect.left   = pt.x;
		ti.rect.right  = pt.x+1;
		ti.rect.top    = pt.y;
		ti.rect.bottom = pt.y+1;
		m_wndToolTip.SendMessage(TTM_NEWTOOLRECT,   0, (LPARAM)&ti);
		
		RelayEvent(uMsg, wParam, lParam);
	}
	return 0;
}
  5. Link the project to Comctl32.lib. You can do either by specifying this library name on linker settings of project/settings dialog box (or) by adding this LIB manually to the project.

Using MFC's CToolTipCtrl class

  1. Add MFC support to ATL project. To use MFC's CToolTipCtrl class, an ATL application should support MFC in the first place. You could do this by selecting Support MFC option in Step1 of ATL/COM AppWizard for ATL DLLs. If the project has already been created without MFC support, you will have to add MFC support manually. The following article shows how to add MFC support ATL DLL/EXE:

    173974 How to add MFC support to an ATL project

  2. Use CToolTipCtrl instead of CWindow for m_wndToolTip member of control class.
  3. Call methods of CToolTipCtrl instead of sending messages.
    HRESULT InPlaceActivate(LONG iVerb, const RECT* prcPosRect=NULL)
	{
		AFX_MANAGE_STATE(AfxGetStaticModuleState());
		CWnd parent;

		HRESULT hr;

		hr = CComControlBase::InPlaceActivate(iVerb, prcPosRect);
		if (m_wndToolTip.m_hWnd == NULL)
		{
			if (m_bWndLess)
			{
				HDC hDC;
				// Get the HDC from the client
				m_spInPlaceSite->GetDC(NULL, OLEDC_NODRAW, &hDC);
				m_hTheWnd = WindowFromDC(hDC);
				m_spInPlaceSite->ReleaseDC(hDC);
			}
			else
				m_hTheWnd = m_hWnd;

			::InitCommonControls();
			parent.Attach(m_hTheWnd);
			RECT rect = {0,0,0,0};
			if (!m_wndToolTip.Create(&parent))
				TRACE("Unable to create tip window.\n");
			else if (!m_wndToolTip.AddTool(&parent, LPCTSTR("TTip2 Control"),&rect, 1))
				TRACE("Unable to add tip for the control window.\n");
			else
				m_wndToolTip.Activate(TRUE);
			parent.Detach();
		}
		return hr;
	}

	void RelayEvent(UINT message, WPARAM wParam, LPARAM lParam)
	{
		if (NULL != m_wndToolTip.m_hWnd)
		{
			MSG msg;

			msg.hwnd= m_hTheWnd;
		    msg.message= message;
			msg.wParam= wParam;
			msg.lParam= lParam;
			msg.time= 0;
			msg.pt.x= LOWORD (lParam);
			msg.pt.y= HIWORD (lParam);

			m_ttip.RelayEvent(&msg);
		}
	} 
	LRESULT OnMouseMove(UINT uMsg, WPARAM wParam, LPARAM lParam,BOOL& bHandled)
	{
		if (m_wndToolTip.m_hWnd)
		{
			POINT pt;
			static uId;
			pt.x = LOWORD(lParam);
			pt.y = HIWORD(lParam);

			TOOLINFO ti;
			ti.cbSize = sizeof(TOOLINFO);
			ti.hwnd   = m_hTheWnd;
			uId = 1;
			ti.uId    = uId;
			ti.rect.left   = pt.x;
			ti.rect.right  = pt.x+1;
			ti.rect.top    = pt.y;
			ti.rect.bottom = pt.y+1;
			m_ttip.SendMessage(TTM_NEWTOOLRECT,   0, (LPARAM)&ti);
		}
		RelayEvent(uMsg, wParam, lParam);
		return 0;
	}

	LRESULT OnLButtonDown(UINT uMsg, WPARAM wParam, LPARAM lParam,BOOL bHandled)
	{
		bHandled = FALSE;
		RelayEvent(uMsg, (WPARAM)wParam,MAKELPARAM(LOWORD(lParam), HIWORD(lParam)));
		return 0L; 
	}

Using ATLCON's CToolTipCtrl class

  1. Copy Atlcontrols.h file from ATLCON to your control project's directory and add it to the project.
  2. Include it in the Stdafx.h file.
  3. Use CToolTipCtrl as you use MFC's CToolTipCtrl class.

REFERENCES

Visual C++ online documentation: Using the ATL COM AppWizard Step 2: Adding a Control For more information, click the following article number to view the article in the Microsoft Knowledge Base:

134209 How to use the ToolTip common control

173974 How to add MFC support to an ATL project

223439 How to using class wrappers to access Windows common controls in ATL

141871 How to add tooltips to ActiveX controls


Additional query words: ATL ActiveX tooltip

Keywords: kbhowto kbtooltip kbctrlcreate KB201540


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