不注册调用ActiveX Dll

雨点打透心脏的1/2处 2021-11-23 19:06 288阅读 0赞

每个ActiveX Dll都应该有个DllGetClassObject函数,利用该函数就可以直接创建所需的com对象,而不需要通过注册表(或者注册)。

STDAPI DllGetClassObject(
      REFCLSID rclsid,  //CLSID for the class object
      REFIID riid,      //Reference to the identifier of the interface 
                        // that communicates with the class object
      LPVOID * ppv      //Address of output variable that receives the 
                        // interface pointer requested in riid
    );

这里必须知道两样东西,一个rclsid,就是需要创建的com对象的CLSID,另一个是 riid,该对象的一个接口的 id.  
然而,调用DllGetClassObject,并不能直接创建所需要的对象,但可以得到对应的 IClassFactory,再由 IClassFactory.CreateInstance得到所需的对象.  
vb实现代码大概如下:  
需要用到一个库,http://www.mvps.org/emorcillo/download/vb6/tl\_ole.zip  
(引用页,http://www.mvps.org/emorcillo/en/code/vb6/wbframe.shtml)  
另外,也将那个ActiveX Dll引用进工程,这里,并不是需要注册它,而是为了方便使用它的方法,因为并没有使用new来创建对象,  
程序编译后即使不注册那个Dll文件都能够正常使用.

Option Explicit
    
    '假设ActiveX Dll 的文件名为dllDemo.dll,并且处于工程同一目录
    Private Declare Function DllGetClassObject Lib "dllDemo.dll" ( _
        rclsid As UUID, riid As UUID, ByRef ppv As Any) As Long
    
    'class id
    Private Const ClsStr_Obj As String = "{C1A334BA-D1A4-48D0-98D5-47FE934961DF}"
    '接口id
    Private Const IidStr_Ins As String = "{231114D5-E046-4DAE-B192-0AB49D493A85}"
    
    'IClassFactory id
    Private Const strIID_IClassFactory As String = "{00000001-0000-0000-C000-000000000046}"
    
    Private ClsId_Obj As UUID
    Private Iid_Ins As UUID
    Private iid_iunknow As UUID
    Private iid_iclassfactory As UUID
    
    
    Private Sub Command1_Click()
    Dim tobj As olelib.IUnknown
    Dim tobj2 As dllDemo.IDemo
    Dim tFac As olelib.IClassFactory
    
    Call DllGetClassObject(ClsId_Obj, iid_iclassfactory, tFac)
    
    tFac.CreateInstance Nothing, iid_iunknow, tobj
    Set tFac = Nothing
    Set tobj2 = tobj
    
    '调用IDemo.Test测试所创建的对象
    tobj2.Test
    End Sub
    
    Private Sub Form_Load()
    '将string转换为 UUID
    CLSIDFromString ClsStr_Obj, ClsId_Obj
    CLSIDFromString IidStr_Ins, Iid_Ins
    CLSIDFromString IIDSTR_IUnknown, iid_iunknow
    CLSIDFromString strIID_IClassFactory, iid_iclassfactory
    End Sub

至此,问题似乎已经解决了,只要为不同的ActiveX Dll编写对应的DllGetClassObject函数就可以了,只是当文件名未定时就比较难办了,例如编写插件时.  
解决办法是用LoadLibrary动态的调用各个dll上的DllGetClassObject.可惜的是vb不支持函数指针.我的办法是借助vc来解决.用vc写dll供vb调用,主要代码如下:

// CrCom.cpp : Defines the entry point for the DLL application.  
//

\#include "stdafx.h"  
\#include <unknwn.h>  
\#include <objbase.h>

typedef int (CALLBACK \*MYPROC)(REFCLSID,REFIID,LPVOID \*);

BOOL APIENTRY DllMain( HANDLE hModule,  
DWORD ul\_reason\_for\_call,  
LPVOID lpReserved  
)  
\{  
return TRUE;  
\}

// if(riid==NULL)riid=&IID\_IUnknown  
int \_stdcall CrComObj(  
LPCSTR lpDll,  
CLSID \*rclsid,  
IID \*riid,  
LPVOID \* ppv)  
\{  
HINSTANCE hinstLib;  
MYPROC ProcAdd;

BOOL fFreeResult, fRunTimeLinkSuccess = FALSE;  
int rtn=0;  
// Get a handle to the DLL module.  
hinstLib = LoadLibrary(lpDll);  
// If the handle is valid, try to get the function address.  
if (hinstLib != NULL)  
\{  
ProcAdd =(MYPROC)GetProcAddress(hinstLib, "DllGetClassObject");  
// If the function address is valid, call the function.  
if (fRunTimeLinkSuccess = (ProcAdd != NULL))  
\{  
if(rclsid==NULL)  
\{  
FreeLibrary(hinstLib);  
return 0;  
\}  
if(riid==NULL)

riid=(IID \*)&IID\_IUnknown;

IClassFactory \*pIf;  
pIf=NULL;  
if(ProcAdd(\*rclsid,IID\_IClassFactory,(void \*\*)&pIf)==S\_OK && pIf!=NULL)  
\{  
if(pIf->CreateInstance(NULL,\*riid,ppv)==S\_OK)  
rtn=(int)hinstLib;  
pIf->Release();  
pIf=NULL;  
\}  
\}  
// Free the DLL module.  
if(!rtn)fFreeResult = FreeLibrary(hinstLib);  
\}  
return rtn;  
\}

// if strriid==NULL, use IID\_IUnknown;  
int \_stdcall CrComObj2(  
LPCSTR lpDll,  
LPCSTR strrclsid,  
LPCSTR strriid,  
LPVOID \* ppv )  
\{  
HINSTANCE hinstLib;  
MYPROC ProcAdd;

BOOL fFreeResult, fRunTimeLinkSuccess = FALSE;  
int rtn=0;  
// Get a handle to the DLL module.  
hinstLib = LoadLibrary(lpDll);  
// If the handle is valid, try to get the function address.  
if (hinstLib != NULL)  
\{  
ProcAdd =(MYPROC)GetProcAddress(hinstLib, "DllGetClassObject");  
// If the function address is valid, call the function.  
if (fRunTimeLinkSuccess = (ProcAdd != NULL))  
\{  
CLSID rclsid;  
IID riid;  
if(strrclsid==NULL)  
\{  
FreeLibrary(hinstLib);  
return 0;  
\}  
CLSIDFromString((LPOLESTR )strrclsid,&rclsid);

if(strriid!=NULL)  
CLSIDFromString((LPOLESTR )strriid,&riid);  
else  
riid=IID\_IUnknown;

IClassFactory \*pIf=NULL;

if(ProcAdd(rclsid,IID\_IClassFactory,(void \*\*)&pIf)==S\_OK && pIf!=NULL)  
\{  
if(pIf->CreateInstance(NULL,riid,ppv)==S\_OK)  
rtn=(int)hinstLib;  
pIf->Release();  
pIf=NULL;  
\}  
\}  
// Free the DLL module.  
if(!rtn)fFreeResult = FreeLibrary(hinstLib);  
\}  
return rtn;  
\}

在vb中的使用方法,CrComObj传递的是UUID,CrComObj2传递的是String,

'函数声明  
Private Declare Function CrComObj Lib "CrCom.dll" ( \_  
ByVal lpDll As String, ByVal rclsid As Long, ByVal riid As Long, ByRef ppv As Any) As Long  
Private Declare Function CrComObj2 Lib "CrCom.dll" ( \_  
ByVal lpDll As String, ByVal strrclsid As Long, ByVal strriid As Long, ByRef ppv As Any) As Long

Dim tobj As olelib.IUnknown  
Dim tobj2 As dllDemo.IDemo

hlib = CrComObj(App.Path & "\\dllDemo.dll", VarPtr(ClsId\_Obj), 0, tobj)  
Set tobj2 = tobj  
tobj2.Test

'或者

hlib=CrComObj2(App.Path & "\\dllDemo.dll", StrPtr(ClsStr\_Obj), 0, tobj)  
Set tobj2 = tobj  
tobj2.Test

CrComObj与CrComObj2返回的是LoadLibrary的返回值,必要的时候需要用FreeLibrary释放.

后记:  
我的多页面浏览器LE中,也实现了不注册调用ActiveX Dll,我是直接使用了一本书(Advanced Visual Basic)的代码,代码颇长,似乎也挺复杂,原先使用的时候也不明所以然,后来终于搞清楚了,其原理是一样的,但是因为vb不支持函数指针,于是它花了很大力气去处理这个问题.相比而言,我觉得还是借用一下vc比较好,这样的话简捷的多.

转载于:https://www.cnblogs.com/MaxWoods/archive/2010/07/20/1781533.html