An ATL Component in C++ that fires COM events

// IPC.h : Declaration of the CIPC
#pragma once
#include "resource.h"       // main symbols
#include <atlctl.h>
#include "InterProcessComms.h"
#include "_IIPCEvents_CP.h"

// My additonal defines
#define HIDDEN_WIN_NAME "NBD_IPC_COMMS_HIDDEN"
#define HIDDEN_WIN_GUID "6845D89A-A80C-4e54-9D94-AE2BBBE182E3"
#define HIDDEN_PROP_DATA_VALUE  (HANDLE) 1

// CIPC
class ATL_NO_VTABLE CIPC : 
	public CComObjectRootEx<CComSingleThreadModel>,
	public IDispatchImpl<IIPC, &IID_IIPC, &LIBID_InterProcessCommsLib, /*wMajor =*/ 1, /*wMinor =*/ 0>,
	public IPersistStreamInitImpl<CIPC>,
	public IOleControlImpl<CIPC>,
	public IOleObjectImpl<CIPC>,
	public IOleInPlaceActiveObjectImpl<CIPC>,
	public IViewObjectExImpl<CIPC>,
	public IOleInPlaceObjectWindowlessImpl<CIPC>,
	public IConnectionPointContainerImpl<CIPC>,
	public CProxy_IIPCEvents<CIPC>, 
	public CComCoClass<CIPC, &CLSID_IPC>,
	public CComControl<CIPC>
{
public:

	CIPC()
		: m_msg_hWnd(0)
		, oldWndProc(0)
	{
	}

DECLARE_OLEMISC_STATUS(OLEMISC_RECOMPOSEONRESIZE | 
	OLEMISC_INVISIBLEATRUNTIME |
	OLEMISC_CANTLINKINSIDE | 
	OLEMISC_INSIDEOUT | 
	OLEMISC_ACTIVATEWHENVISIBLE | 
	OLEMISC_SETCLIENTSITEFIRST
)

DECLARE_REGISTRY_RESOURCEID(IDR_IPC)

BEGIN_COM_MAP(CIPC)
	COM_INTERFACE_ENTRY(IIPC)
	COM_INTERFACE_ENTRY(IDispatch)
	COM_INTERFACE_ENTRY(IViewObjectEx)
	COM_INTERFACE_ENTRY(IViewObject2)
	COM_INTERFACE_ENTRY(IViewObject)
	COM_INTERFACE_ENTRY(IOleInPlaceObjectWindowless)
	COM_INTERFACE_ENTRY(IOleInPlaceObject)
	COM_INTERFACE_ENTRY2(IOleWindow, IOleInPlaceObjectWindowless)
	COM_INTERFACE_ENTRY(IOleInPlaceActiveObject)
	COM_INTERFACE_ENTRY(IOleControl)
	COM_INTERFACE_ENTRY(IOleObject)
	COM_INTERFACE_ENTRY(IPersistStreamInit)
	COM_INTERFACE_ENTRY2(IPersist, IPersistStreamInit)
	COM_INTERFACE_ENTRY(IConnectionPointContainer)
END_COM_MAP()

BEGIN_PROP_MAP(CIPC)
	PROP_DATA_ENTRY("_cx", m_sizeExtent.cx, VT_UI4)
	PROP_DATA_ENTRY("_cy", m_sizeExtent.cy, VT_UI4)
	// Example entries
	// PROP_ENTRY("Property Description", dispid, clsid)
	// PROP_PAGE(CLSID_StockColorPage)
END_PROP_MAP()

BEGIN_CONNECTION_POINT_MAP(CIPC)
	CONNECTION_POINT_ENTRY(__uuidof(_IIPCEvents))
END_CONNECTION_POINT_MAP()

BEGIN_MSG_MAP(CIPC)
	CHAIN_MSG_MAP(CComControl<CIPC>)
	DEFAULT_REFLECTION_HANDLER()
END_MSG_MAP()
// Handler prototypes:
//  LRESULT MessageHandler(UINT uMsg, WPARAM wParam, LPARAM lParam, BOOL& bHandled);
//  LRESULT CommandHandler(WORD wNotifyCode, WORD wID, HWND hWndCtl, BOOL& bHandled);
//  LRESULT NotifyHandler(int idCtrl, LPNMHDR pnmh, BOOL& bHandled);

// IViewObjectEx
	DECLARE_VIEW_STATUS(VIEWSTATUS_SOLIDBKGND | VIEWSTATUS_OPAQUE)

// IIPC
public:
		HRESULT OnDraw(ATL_DRAWINFO& di)
		{
		RECT& rc = *(RECT*)di.prcBounds;
		// Set Clip region to the rectangle specified by di.prcBounds
		HRGN hRgnOld = NULL;
		if (GetClipRgn(di.hdcDraw, hRgnOld) != 1)
			hRgnOld = NULL;
		bool bSelectOldRgn = false;

		HRGN hRgnNew = CreateRectRgn(rc.left, rc.top, rc.right, rc.bottom);

		if (hRgnNew != NULL)
		{
			bSelectOldRgn = (SelectClipRgn(di.hdcDraw, hRgnNew) != ERROR);
		}

		Rectangle(di.hdcDraw, rc.left, rc.top, rc.right, rc.bottom);
		SetTextAlign(di.hdcDraw, TA_CENTER|TA_BASELINE);
		LPCTSTR pszText = _T("ATL 7.0 : IPC");
		TextOut(di.hdcDraw, 
			(rc.left + rc.right) / 2, 
			(rc.top + rc.bottom) / 2, 
			pszText, 
			lstrlen(pszText));

		if (bSelectOldRgn)
			SelectClipRgn(di.hdcDraw, hRgnOld);

		return S_OK;
	}


	DECLARE_PROTECT_FINAL_CONSTRUCT()

	// Constructor for the IPC class object
	HRESULT FinalConstruct()
	{
		m_msg_hWnd = CIPC::InitComms();
		if (m_msg_hWnd == 0 ) {
			// there is an error
			return E_FAIL;
		}
		return S_OK;
	}

	// Destructor
	void FinalRelease() 
	{
		CIPC::EndComms();
	}

private:
	// This holds the hWnd of our hidden window used to pass messages
	HWND m_msg_hWnd;
	// Create an array of HWNDs for storing the hidden window handles
	CSimpleArray<HWND> m_hWndArray;
	// Storage for the old WndProc address
	long oldWndProc;

public:
	// Property function to return the handle of the hidden windo
	STDMETHOD(get_msghWnd)(LONG* pVal);
	// Method used to send data
	STDMETHOD(SendData)(LONG lData, BSTR sData, LONG hWnd);
	// Window proc function
	LRESULT MyWndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam);

private:
	// Private function to init the IPC
	HWND InitComms(void);
	// // Private function to end the IPC
	int EndComms(void);
	// Start the enumeration of all top level windows, to find all our hidden msg windows
	int EnumerateWindows(void);
	// The call back function for Enumerate Windows
	BOOL CIPC::EnumWindowsProc(HWND hWnd, DWORD lParam);

	// The global static member function that can be used as a function for
	static LRESULT CALLBACK GlobalWndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam);
};

OBJECT_ENTRY_AUTO(__uuidof(IPC), CIPC)