让vc6和最新的msdn集成

王朝vc·作者佚名  2006-01-09
窄屏简体版  字體: |||超大  

http://www.codeproject.com/macro/VSNetHelp.asp

Integrate latest MSDN with VC6 and Hook functions of COM

By Chunhua Liu

Introduction

After Oct. 2001, you cannot get help by pressing F1 in VC6 with latest MSDN.

Microsoft has changed the help format from CHM to document explorer.

? Is it possible to use latest MSDN in VC6?

? The answer is YES!

Details

First, we must know how VC6 brings up the help after you press F1. This is

easy if you have a debugger such as Soft-ICE.

If you don't install MSDN, after you press F1, VC6 will popup a message box

says you haven't installed MSDN. Set a breakpoint at MessageBox. Press F1

and debugger will popup. Look at the stack. You will see this function was

called from "C:\Program Files\Common Files\Microsoft

Shared\VS98\vshelp.dll".

Then we use Dependency Walker ("depends" in Visual Studio Tools) to see

what functions are exported. We will see DllRegisterServer and

DllUnregisterServer. It's obviously a COM.

Use VC6 to create a simple console project. Add the following line to your

.cpp file.

#import "C:\Program Files\Common Files\Microsoft Shared\VS98\vshelp.dll"

And build your project.

Open the Debug directory, you will find "vshelp.tlh" and "vshelp.tli"

Open "vshelp.tlh", you will see:

struct __declspec(uuid("854d7ac0-bc3d-11d0-b421-00a0c90f9dc4"))

IVsHelpSystem : IUnknown

{

//

// Wrapper methods for error-handling

//

HRESULT KeywordSearch (

LPWSTR pszKeyword,

long dwFlags,

long dwReserved );

HRESULT ALinkSearch (

LPWSTR pszALink,

long dwFlags,

long dwReserved );

...

The function KeywordSearch was called when you press F1. So if we replace

this function and call latest MSDN's help function, it should work.

Then how to do this? Since it's a COM interface, it's easy to hook it.

Basically a COM interface is a C++ class with virtual table. It has a

pointer to a table contains all virtual functions address. And this table

is shared by all instances. So we only need change the function address in

the table. And this interface will look like:

struct _IVsHelpSystemVtbl{

HRESULT (STDMETHODCALLTYPE *QueryInterface)(IUnknown * This,

REFIID riid, void **ppvObject);

ULONG (STDMETHODCALLTYPE *AddRef)(IUnknown * This);

ULONG (STDMETHODCALLTYPE *Release)(IUnknown * This);

HRESULT (STDMETHODCALLTYPE *KeywordSearch)(IUnknown * This,

LPWSTR pszKeyword, long dwFlags, long dwReserved);

};

struct _IVsHelpSystem

{

struct _IVsHelpSystemVtbl *lpVtbl;

};

What we need to do now is create an instance of this COM. And we will get

the address of the table. Now we need to know how to bring up the help of

latest MSDN. It seems it's not documented. It's also a COM.

Add the following line to your .cpp file. You will get the COM definition.

#import "C:\Program Files\Common Files\Microsoft Shared\MSEnv\vshelp.tlb"

In "vshelp.tlh", you can find function:

HRESULT DisplayTopicFromF1Keyword ( _bstr_t pszKeyword );

Obviously, this is what we need. So in the function KeywordSearch, call

DisplayTopicFromF1Keyword will launch the latest MSDN.

Here is the code:

HRESULT hr = theHelp.CreateInstance(__uuidof(VsHelp::DExploreAppObj));

if (SUCCEEDED(hr))

{

HRESULT hr = vc6Help.CreateInstance(

__uuidof(VsHelpServices::VsHelpServices));

if (SUCCEEDED(hr))

{

iHelp = (_IVsHelpSystem *)vc6Help.GetInterfacePtr();

TRACE1("iHelp = %x\n", iHelp);

TRACE1("lpVtbl = %x\n", iHelp->lpVtbl);

TRACE1("KeywordSearch = %x\n", iHelp->lpVtbl->KeywordSearch);

OldKeywordSearch = iHelp->lpVtbl->KeywordSearch;

DWORD dwOldProtect;

if (VirtualProtect(iHelp->lpVtbl, sizeof(

_IVsHelpSystemVtbl), PAGE_READWRITE, &dwOldProtect))

iHelp->lpVtbl->KeywordSearch = MyKeywordSearch;

}

}

Easy, right? There are two things you must keep in mind. First we must

declare the vc6Help in global space and release it when program quit.

This is because the vshelp.dll will be freed if there is no more instance.

If so, then what we modified will be gone with it. The second, we must call

VirtualProtect to make the virtual table become writable, otherwise you

cannot modify the virtual table because it's read only.

How to use it?

Click VC6's menu "Tools"->"Customize"->"Add-ins and Macro Files"->"Browse".

Then choose "VSNetHelp.dll", click "Close".

Move the caret to a keyword, press F1. You got it!

 
 
 
免责声明:本文为网络用户发布,其观点仅代表作者个人观点,与本站无关,本站仅提供信息存储服务。文中陈述内容未经本站证实,其真实性、完整性、及时性本站不作任何保证或承诺,请读者仅作参考,并请自行核实相关内容。
 
 
© 2005- 王朝網路 版權所有 導航