[
object,
uuid(00020400-0000-0000-C000-000000000046),
//IDispatch接口的IID =IID_IDispatch
pointer_default(unique)
]

interface IDispatch : IUnknown
{
typedef [unique] IDispatch * LPDISPATCH; // 转定义 IDispatch * 为 LPDISPATCH

    HRESULT GetTypeInfoCount([out] UINT * pctinfo); 
HRESULT GetTypeInfo([in] UINT iTInfo,[in] LCID lcid,
[out] ITypeInfo ** ppTInfo);

    HRESULT GetIDsOfNames(     // 根据函数名字，取得函数序号(DISPID)
[in] REFIID riid,
[in, size_is(cNames)] LPOLESTR * rgszNames,
[in] UINT cNames,
[in] LCID lcid,
[out, size_is(cNames)] DISPID * rgDispId
);

    [local]         //本地版函数
HRESULT Invoke(  
[in] DISPID dispIdMember,
[in] REFIID riid,
[in] LCID lcid,
[in] WORD wFlags,
[in, out] DISPPARAMS * pDispParams,
[out] VARIANT * pVarResult,
[out] EXCEPINFO * pExcepInfo,
[out] UINT * puArgErr
);

    [call_as(Invoke)]       //远程版函数
HRESULT RemoteInvoke(
[in] DISPID dispIdMember,
[in] REFIID riid,
[in] LCID lcid,
[in] DWORD dwFlags,
[in] DISPPARAMS * pDispParams,
[out] VARIANT * pVarResult,
[out] EXCEPINFO * pExcepInfo,
[out] UINT * pArgErr,
[in] UINT cVarRef,
[in, size_is(cVarRef)] UINT * rgVarRefIdx, 
[in, out, size_is(cVarRef)] VARIANTARG * rgVarRef
);
}

import "oaidl.idl";
import "ocidl.idl";
[
object,
uuid(DAB964C5-24E5-4648-8765-F8D8AA9D6F23),
dual,
helpstring("IDFun Interface"),
pointer_default(unique)
]
interface IDFun : IDispatch
{
[id(1), helpstring("method Add")] HRESULT Add([in]long n1,[in]long
n2,[out,retval]long* pVal );
};

[
uuid(51000335-57C3-4D25-8A05-8768264350F0),
version(1.0),
helpstring("Object 1.0 Type Library")
]
library OBJECTLib
{
importlib("stdole32.tlb");
importlib("stdole2.tlb");

 [
uuid(DF7E08FC-51B3-4498-9D14-63E5E704133E),
helpstring("DFun Class")
]
coclass DFun
{
[default] interface IDFun;
};

Add([in] VARIANT v1, [in] VARIANT v2, [out, retval] VARIANT * pVal);
Upper([in] BSTR str, [out,retval] BSTR * pVal);

/************************************************************************/
/* 转换为小写
/************************************************************************/
STDMETHODIMP CDFun::Lower(BSTR bstr, BSTR *pVal)
{
*pVal = NULL; 
CComBSTR s(bstr);
s.ToLower(); // 转换为小写
*pVal = s.Copy();
return S_OK;
}
/************************************************************************/
/* 加法运算
/* 整数的加法运算和字符串的加法运算
/************************************************************************/
STDMETHODIMP CDFun::Add(VARIANT  v1, VARIANT  v2,VARIANT*  pVal)
{
::VariantInit( pVal ); 

     CComVariant v_1( v1 );
CComVariant v_2( v2 );

 if((v1.vt & VT_I4) && (v2.vt & VT_I4) ) // 如果都是整数类型
{ 
v_1.ChangeType( VT_I4 );   // 转换为整数
v_2.ChangeType( VT_I4 );   // 转换为整数

     pVal->vt = VT_I4;
pVal->lVal = v_1.lVal + v_2.lVal; // 加法
}
else
{
v_1.ChangeType( VT_BSTR );   // 转换为字符串
v_2.ChangeType( VT_BSTR );   // 转换为字符串

     CComBSTR bstr( v_1.bstrVal );
bstr.AppendBSTR( v_2.bstrVal ); // 字符串连接

     pVal->vt = VT_BSTR;
pVal->bstrVal = bstr.Detach();
}
return S_OK;
}

Set obj = CreateObject("Object.DFun")
MsgBox obj.Lower("接口函数Lower：THIS　IS  A TEST")
MsgBox obj.Add("1+2=" ,obj.Add(1,2))
Set obj = Nothing