COM

1. Create a simple ATL Object.
   
2. Create an event interface (dispinterface, see MSDN docs)
   
3. Right click on the ATL class generated in step 1 and choose Add Connection Point. Select your event interface, and click ok.
   
4. Use the Fire_XX methods generated by the event proxy class.
   

// IMyInterface manually written (but could be the result of MIDL compilation of IMyInterface.idl).
class IMyInterface : public IUnknown
{
    virtual HRESULT __stdcall Method1(...)=0;
    virtual HRESULT __stdcall Method2(...)=0;
};


class MyInterfaceImpl : public IMyInterface
{
 protected:
    int m_SomeMember;

 public:
    // IUnknown implementation
    virtual HRESULT __stdcall QueryInterface(const IID& iid, void** ppv) ;
    virtual ULONG __stdcall AddRef() ;
    virtual ULONG __stdcall Release() ;

    // IMyInterface implementation
    virtual HRESULT __stdcall Method1(...);
    virtual HRESULT __stdcall Method2(...);
}

#ifndef _WIN32_WINNT<br />
#define _WIN32_WINNT 0x0400<br />
#endif

\selman\desktop\workarea\comclienta\cpp1.cpp(27) : error C2664: 'CoCreateInstance' : cannot convert parameter 1 from 'char [37]' to 'const struct _GUID &'
        Reason: cannot convert from 'char [37]' to 'const struct _GUID'
        No constructor could take the source type, or constructor overload resolution was ambiguous

	/*	HEADER FILES	*/

#include<iostream.h>
	// Definitions/Declarations for iostream classes
#include<objbase.h>
	// Component object model defintions
#include<comdef.h>	
        // Native C++ compiler COM support 

HRESULT hr;


int main()
{
	IActiveDesktop *pIActiveDesktop; 

	// Initialize the COM system
	CoInitialize ( NULL );	    
	
	// Retrives a COM interface using CoCreateInstance
	hr = CoCreateInstance(	"75048700-ef1f-11d0-9888-006097deacf9",
							NULL, 
							CLSCTX_INPROC_SERVER, 
							"f490eb00-1240-11d1-9888-006097deacf9", 
							(void**) &pIActiveDesktop);//:confused: IT GIVES ERROR ONLY THIS LINE

	cout<<hr<<"\n";

	cout<<hr;


	return 0;	
}

<br />
CComPtr<IActiveDesktop> spActDesktop;<br />
spActDesktop.CoCreateInstance( CLSID_ActiveDesktop );

DEFINE_GUID( CLSID_ActiveDesktop, 0x75048700L, 0xEF1F, 0x11D0, 0x98, 0x88, 0x00, 0x60, 0x97, 0xDE, 0xAC, 0xF9);
DEFINE_GUID( IID_IActiveDesktop, 0xF490EB00L, 0x1240, 0x11D1, 0x98, 0x88, 0x00, 0x60, 0x97, 0xDE, 0xAC, 0xF9);