4、错误"no GUID has been associated with this object"的解决方法

[问题描述]

用VS2008编译windows shell时,成功；相同的方法在VS2005下，提示错误：

error C2787: 'IContextMenu' : no GUID has been associated with this object

error C2440: 'initializing' : cannot convert from 'DWORD_PTR' to 'const IID *'

error C2440: 'initializing' : cannot convert from 'ATL::_ATL_CREATORARGFUNC (__stdcall *)' to 'DWORD_PTR'

[解决方法]

关键的问题是以下头文件没有包含正确

#include "shlobj.h"

#include "comdef.h"

#include <shlguid.h>

下面是收集的一些问题解决过程：

1、Have you downloaded the Latest Platfrom SDK? If so, are your vc dirs pointing to the proper include dirs, eg: shlguid.h is getting picked up from the SDK\include and not the vc98\include. You set those in the tools-Options->directories->include dirs for VC

2、There are two <comdef.h> header files in VC.NET, one in Vc7/include and the other in Vc7/PlatformSDK/include. The former splits off the smart pointer typedefs into comdefsp.h, and it doesn't include IContextMenu. The latter does. You can try to #include the PlatformSDK header directly, change your INCLUDE path order, or supply the missing typedef yourself, e.g.

struct __declspec(uuid("000214e4-0000-0000-c000-000000000046"))

IContextMenu;

_COM_SMARTPTR_TYPEDEF(IContextMenu, __uuidof(IContextMenu));

3、怎样找到Interface的GUID?

我在注册表 HKCR\Interface\ 下可以找到形式为

{aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee}的键，如果其下有默认项="Interface",则说明这个键就是该Interface的GUID。

有没有其它方法？

(1) VC6\common\Tools 下有个OLE/COM Object Viewer 很方便，但在VC2005下就没找到这个工具

(2) PlatformSDK\include\comdef.h 中也有GUID的定义

4、__uuidof它是C++ 运算符

[总结]

如上所述，如果把PlatformSDK/include放在前面仍然不可以的话，就下载新的SDK，把include目录包含进去就好了。个人感觉手动添加这些uuid值如，struct __declspec(uuid("000214e4-0000-0000-c000-000000000046"))

IContextMenu;

_COM_SMARTPTR_TYPEDEF(IContextMenu, __uuidof(IContextMenu));

过了这个村，还会有下个店，还不如直接更新一下SDK来得直接保险。

参考：

[1] 比较杂，没有记录出处。可以GOOGLE到。