com（用DLL） 的例子

Comdll  的编写

inface.h

----------------------

#ifdef   _INFACE_H

#else  

#define _INFACE_H

#include <objbase.h> 

interface IX:public IUnknown

{

virtual ULONG  __stdcall fx()=0;

};

interface IY:public IUnknown 

{

virtual void __stdcall fy()=0;

};

interface IZ:public IUnknown

{

virtual void __stdcall fz()=0;

};

class CA:public IX

{

virtual  HRESULT __stdcall QueryInterface (const IID & riid,void **ppv);

virtual  ULONG  __stdcall AddRef();

virtual ULONG __stdcall Release();

virtual ULONG   __stdcall fx();

public:

CA();

~CA();

private:

long m_cRef;

};

extern "C"

{ 

const IID IID_IX;

const IID IID_IY;

const IID IID_IZ;

}

#endif

------------------

compnt1.cpp

----------------------------------

#include "inface.h"

#include <objbase.h>

CA::CA()

{

m_cRef=0;

}

CA::~CA()

{

OutputDebugString("~ destructor \n");

}

HRESULT __stdcall CA::QueryInterface (const IID & riid,void **ppv)

{

if(riid==IID_IUnknown)

{

*ppv=static_cast<IX*>(this);

}

else if(riid==IID_IX)

{

*ppv=static_cast<IX*>(this);

}

/*

else if(riid==IID_IY)

{

*ppv = static_cast<IY*>(this);

}*/

else

{

*ppv=NULL;

return E_NOINTERFACE;

}

static_cast<IUnknown *>(*ppv)->AddRef();

return S_OK;

}

ULONG  __stdcall CA::AddRef()

{

return InterlockedIncrement(&m_cRef);

}

ULONG __stdcall CA::Release()

{

return InterlockedDecrement(&m_cRef);

}

ULONG __stdcall CA::fx()

{

long a=10;

return a;

}

extern "C" IUnknown * CreateInstance()

{

IUnknown *pI = static_cast<IX*>(new CA());

pI->AddRef();

return pI;

}

-----------------------

guids.cpp

------------------------------

#include <objbase.h>

// {73373F3A-716D-488b-A821-2A0E963B6285}

extern  const GUID IID_IX = 

{ 0x73373f3a, 0x716d, 0x488b, { 0xa8, 0x21, 0x2a, 0xe, 0x96, 0x3b, 0x62, 0x85 } };

// {D8FED3FB-31D6-48c0-8FBA-E1B613281D36}

extern const GUID IID_IY = 

{ 0xd8fed3fb, 0x31d6, 0x48c0, { 0x8f, 0xba, 0xe1, 0xb6, 0x13, 0x28, 0x1d, 0x36 } };

// {8532846B-94E5-4a10-A632-36A49C5D5D76}

extern  const GUID IID_IZ = 

{ 0x8532846b, 0x94e5, 0x4a10, { 0xa6, 0x32, 0x36, 0xa4, 0x9c, 0x5d, 0x5d, 0x76 } };

----------------

comdll.def       //模块定义软件 

--------------------------------------------------

LIBRARY "Comdll"

EXPORTS 

CreateInstance  @1

--------------------------------------------------------

在     MFC   的中 结合

#include "inface.h"

#include "WinDef.h"

IUnknown * CallCreateInstance(char * name)

{

typedef IUnknown * (* fun)();

fun  func=NULL;

HMODULE hMoudle;

hMoudle=::LoadLibrary(name); //"Comdll.dll"

if(hMoudle)

{

func=(fun)::GetProcAddress(hMoudle,"CreateInstance");

if(func)

{

return func();

}

else

{

AfxMessageBox("func = NULL");

}

}

else

{

AfxMessageBox("DLL faild");

}

return NULL;

}

void CCOMDlltest1Dlg::OnBnClickedOk()

{

// TODO: 在此添加控件通知处理程序代码

//OnOK();

char buf[30];

sprintf(buf,"%s","Comdll.dll");

IUnknown *pi=CallCreateInstance(buf);

IX * ix;

pi->QueryInterface(IID_IX,(void **)&ix);

CString str;

str.Format("%ld",ix->fx());

MessageBox(str);

//typedef 

}