1.假如我们创建的Com组件的工程名叫TestCom,在其中添加了一个接口叫MyCom,接口名会自动命名为IMyCom,在其中添加两个方法，分别为：
C++代码 
HRESULT Add([in] long n1,[in] long n2,[out,retval]long * pVal);
HRESULT Cat([in] BSTR s1,[in] BSTR s2,[out,retval] BSTR * pVal);
[c++] view plain copy
HRESULT Add([in] long n1,[in] long n2,[out,retval]long * pVal);
HRESULT Cat([in] BSTR s1,[in] BSTR s2,[out,retval] BSTR * pVal);
编绎成功后，会生成TestCom.dll
注意此时我们生成的Com组件层次即为：TestCom.IMycom.方法;
2.下面总结出调用该Com的几种方法：
Cpp代码 
#include "stdafx.h"
#include <atlbase.h>
#import "G:\\workspace\\VC_WorkSpace\\TestCom\\Debug\\TestCom.dll" no_namespace
#include "stdafx.h"#include <atlbase.h>#import "G:\\workspace\\VC_WorkSpace\\TestCom\\Debug\\TestCom.dll" no_namespace
/*
注意：在导入了com的dll后，会在工程的exe目录下生成两个文件：TestCom.tlh与TestCom.tli,一个为定义文件，一个为实现文件，打开TestCom.tlh定义文件，会发现有类似这样几句：
_COM_SMARTPTR_TYPEDEF(IMyCom, __uuidof(IMyCom)); //该宏定义了指向接口IMyCom的指针IMyComPtr,以后的程序中可以直接用IMyComPtr这个指针类型。
struct __declspec(uuid("92e83a37-399a-47b1-bf6c-0ab052650cfe"))
MyCom; //该句定义了CLSID为"{92e83a37-399a-47b1-bf6c-0ab052650cfe}",通过它我们可以通过CLSIDFromString获取clsid;
struct __declspec(uuid("103b4c6e-3d3e-4e38-ab50-b9348465fc13"))
IMyCom : IDispatch //该句定义了接口ID:IID为"{103b4c6e-3d3e-4e38-ab50-b9348465fc13}",通过它我们可以通过IIDFromString获取接口iid;
CoCreateInstance函数就用到了上面两个做为参数来创建Com对象.
*/
第一种方法：
Cpp代码 
int impl0()
{
CoInitialize(NULL);
CLSID clsid;
IID iid;
HRESULT hr = CLSIDFromString(OLESTR("{92e83a37-399a-47b1-bf6c-0ab052650cfe}"),&clsid);
if(NOERROR != hr){
MessageBox(NULL,"ErrCLSIDFromString","ErrCLSIDFromString",MB_OK);
return -1;
}
HRESULT hriid = IIDFromString(OLESTR("{103b4c6e-3d3e-4e38-ab50-b9348465fc13}"),&iid);
if(S_OK != hriid){
MessageBox(NULL,"ErrIIDFromString","ErrIIDFromString",MB_OK);
return -1;
}
{
CComPtr<imycom> pMyCom;
pMyCom.CoCreateInstance(clsid);
long ret;
ret = pMyCom->Add(1,2);
}
CoUninitialize();
return 0;
}
int impl0(){CoInitialize(NULL);CLSID clsid;IID iid;HRESULT hr = CLSIDFromString(OLESTR("{92e83a37-399a-47b1-bf6c-0ab052650cfe}"),&clsid);if(NOERROR != hr){MessageBox(NULL,"ErrCLSIDFromString","ErrCLSIDFromString",MB_OK);return -1;}HRESULT hriid = IIDFromString(OLESTR("{103b4c6e-3d3e-4e38-ab50-b9348465fc13}"),&iid);if(S_OK != hriid){MessageBox(NULL,"ErrIIDFromString","ErrIIDFromString",MB_OK);return -1;}{CComPtr<imycom> pMyCom;pMyCom.CoCreateInstance(clsid);long ret;ret = pMyCom->Add(1,2);}CoUninitialize();return 0;}第二种方法：
Cpp代码 
int impl1()
{
CoInitialize(NULL);
CLSID clsid;
CLSIDFromProgID(OLESTR("TestCom.MyCom"),&clsid); //"TestCom.MyCom"即为Dll名+Com对象名
{
CComPtr<imycom> pMyCom;
pMyCom.CoCreateInstance(clsid);
long ret;
ret = pMyCom->Add(1,2);
}
CoUninitialize();
return 0;
}
int impl1(){CoInitialize(NULL);CLSID clsid;CLSIDFromProgID(OLESTR("TestCom.MyCom"),&clsid); //"TestCom.MyCom"即为Dll名+Com对象名{CComPtr<imycom> pMyCom;pMyCom.CoCreateInstance(clsid);long ret;ret = pMyCom->Add(1,2);}CoUninitialize();return 0;}第三种方法：
Cpp代码 
int impl2()
{
CoInitialize(NULL);
IMyComPtr Pt ;
if (!SUCCEEDED(Pt.CreateInstance(__uuidof(MyCom))))
{
DWORD err;
err = GetLastError();
char Msg[128]={0};
sprintf(Msg,"%d",err);
MessageBox(NULL,Msg,"Err",MB_OK);
return -1;
}
long ret = Pt->Add(1,2);
CoUninitialize();
return 0;
}
int impl2(){CoInitialize(NULL);IMyComPtr Pt ;if (!SUCCEEDED(Pt.CreateInstance(__uuidof(MyCom)))){DWORD err;err = GetLastError();char Msg[128]={0};sprintf(Msg,"%d",err);MessageBox(NULL,Msg,"Err",MB_OK);return -1;}long ret = Pt->Add(1,2);CoUninitialize();return 0;}第四种方法：
Cpp代码 
int impl3()
{
CoInitialize(NULL);
IMyComPtr Pt(__uuidof(MyCom)) ;
long ret = Pt->Add(1,2);
CoUninitialize();
return 0;
}
int impl3(){CoInitialize(NULL);IMyComPtr Pt(__uuidof(MyCom)) ;long ret = Pt->Add(1,2);CoUninitialize();return 0;}第五种方法：
Cpp代码 
int impl4()
{
CoInitialize(NULL);
IMyCom * pMyCom=NULL;
CLSID clsid;
IID iid;
HRESULT hr = CLSIDFromString(OLESTR("{92e83a37-399a-47b1-bf6c-0ab052650cfe}"),&clsid);
if(NOERROR != hr){
MessageBox (NULL,"ErrCLSIDFromString","ErrCLSIDFromString",MB_OK);
return -1;
}
HRESULT hriid = IIDFromString(OLESTR("{103b4c6e-3d3e-4e38-ab50-b9348465fc13}"),&iid);
if(S_OK != hriid){
MessageBox(NULL,"ErrIIDFromString","ErrIIDFromString",MB_OK);
return -1;
}
if (!SUCCEEDED(::CoCreateInstance(clsid,NULL,CLSCTX_INPROC_SERVER,iid,(void**)&pMyCom)))
{
DWORD err;
err = GetLastError();
char Msg[128]={0};
sprintf(Msg,"%d",err);
MessageBox(NULL,Msg,"Err",MB_OK);
return -1;
}
long ret;
ret = pMyCom->Add(1,2);
CoUninitialize();
return 0;
}
int impl4(){CoInitialize(NULL);IMyCom * pMyCom=NULL;CLSID clsid;IID iid;HRESULT hr = CLSIDFromString(OLESTR("{92e83a37-399a-47b1-bf6c-0ab052650cfe}"),&clsid);if(NOERROR != hr){MessageBox (NULL,"ErrCLSIDFromString","ErrCLSIDFromString",MB_OK);return -1;}HRESULT hriid = IIDFromString(OLESTR("{103b4c6e-3d3e-4e38-ab50-b9348465fc13}"),&iid);if(S_OK != hriid){MessageBox(NULL,"ErrIIDFromString","ErrIIDFromString",MB_OK);return -1;}if (!SUCCEEDED(::CoCreateInstance(clsid,NULL,CLSCTX_INPROC_SERVER,iid,(void**)&pMyCom))){DWORD err;err = GetLastError();char Msg[128]={0};sprintf(Msg,"%d",err);MessageBox(NULL,Msg,"Err",MB_OK);return -1;}long ret;ret = pMyCom->Add(1,2);CoUninitialize();return 0;}int main(int argc, char* argv[])
{
return impl0();
}