Explorer 左侧面板中的 ContextMenu 处理程序

Question

我正在尝试使用 c++ 编写上下文菜单处理程序。我希望处理程序能够处理所有文件和所有文件夹，以及资源管理器左窗格中的那些。 我开始基于我试图适应我的需求的 CodeProject 项目。我是从here 那里得到的。

到目前为止，一切似乎都按预期工作，除了资源管理器左窗格的文件夹。 在那里我得到一个 AccessViolationException。右键单击和上下文菜单显示之间发生异常。 我删除了不同函数中的代码，直到它再次工作，似乎问题来自 QueryContextMenu 方法。

有人知道我做错了吗？

这是我当前有效的代码（有点明显，因为没有添加任何项目）：

STDMETHODIMP ShellExt::Initialize (LPCITEMIDLIST pidlFolder, LPDATAOBJECT pDataObj, HKEY hProgID )
{
    FORMATETC fmt = { CF_HDROP, NULL, DVASPECT_CONTENT, -1, TYMED_HGLOBAL };
    STGMEDIUM stg = { TYMED_HGLOBAL };
    HDROP     hDrop;

    // Look for CF_HDROP data in the data object.
    if ( FAILED( pDataObj->GetData ( &fmt, &stg ) ))
    {
        // Nope! Return an "invalid argument" error back to Explorer.
        return E_INVALIDARG;
    }

    // Get a pointer to the actual data.
    hDrop = (HDROP) GlobalLock ( stg.hGlobal );

    // Make sure it worked.
    if ( NULL == hDrop )
        return E_INVALIDARG;

    // Sanity check - make sure there is at least one filename.
    UINT uNumFiles = DragQueryFile ( hDrop, 0xFFFFFFFF, NULL, 0 );
    HRESULT hr = S_OK;

    if ( 0 == uNumFiles )
    {
        GlobalUnlock ( stg.hGlobal );
        ReleaseStgMedium ( &stg );
        return E_INVALIDARG;
    }

    // Get the name of the first file and store it in our member variable m_szFile.
    if ( 0 == DragQueryFile ( hDrop, 0, m_szFile, MAX_PATH ) )
        hr = E_INVALIDARG;

    GlobalUnlock ( stg.hGlobal );
    ReleaseStgMedium ( &stg );

    return hr;
}

STDMETHODIMP ShellExt::QueryContextMenu (HMENU hmenu, UINT uMenuIndex, UINT uidFirstCmd, UINT uidLastCmd, UINT uFlags )
{
    return MAKE_HRESULT ( SEVERITY_SUCCESS, FACILITY_NULL, 0 );
}

STDMETHODIMP ShellExt::GetCommandString (UINT_PTR idCmd, UINT uFlags, UINT* pwReserved, LPSTR pszName, UINT cchMax)
{
    return E_INVALIDARG;
}

STDMETHODIMP ShellExt::InvokeCommand (LPCMINVOKECOMMANDINFO pCmdInfo)
{
    return S_OK;
}

但是现在如果我在 ShellExt::QueryContextMenu 中添加一个项目，资源管理器的左窗格会引发异常，而右窗格中的文件和文件夹工作得很好。 我尝试了在互联网上找到的以下两个版本，但都有相同的问题：

STDMETHODIMP ShellExt::QueryContextMenu (HMENU hmenu, UINT uMenuIndex, UINT uidFirstCmd, UINT uidLastCmd, UINT uFlags )
{
    // If the flags include CMF_DEFAULTONLY then we shouldn't do anything.
    if ( uFlags & CMF_DEFAULTONLY )
        return MAKE_HRESULT ( SEVERITY_SUCCESS, FACILITY_NULL, 0 );

    InsertMenu ( hmenu, uMenuIndex, MF_BYPOSITION, uidFirstCmd, _T("Test Item") );

    return MAKE_HRESULT ( SEVERITY_SUCCESS, FACILITY_NULL, 1 );
}

和

STDMETHODIMP ShellExt::QueryContextMenu (HMENU hmenu, UINT uMenuIndex, UINT uidFirstCmd, UINT uidLastCmd, UINT uFlags )
{
    // If the flags include CMF_DEFAULTONLY then we shouldn't do anything.
    if ( uFlags & CMF_DEFAULTONLY )
        return MAKE_HRESULT ( SEVERITY_SUCCESS, FACILITY_NULL, 0 );

    UINT uID = uidFirstCmd;
    UINT pos = uMenuIndex;

    MENUITEMINFO mii = { sizeof(mii) };
    mii.fMask = MIIM_STRING | MIIM_FTYPE | MIIM_ID | MIIM_STATE;
    mii.fType = MFT_STRING;
    mii.dwTypeData = _T("Menu 1");
    mii.fState = MFS_ENABLED;
    mii.wID = uID++;

    if (!InsertMenuItem(hmenu, pos++, TRUE, &mii))
    {
        return HRESULT_FROM_WIN32(GetLastError());
    }

    return MAKE_HRESULT(SEVERITY_SUCCESS, FACILITY_NULL, uID - uidFirstCmd);
}

我在 QueryContextMenu 中得到的参数：
- hmenu = 0x0000000001480405
- uMenuInde​​x = 3
- uidFirstCmd = 148
- uidLastCmd = 32762
- uFlags = 1044

异常详情。

QueryContextMenu 和 GetCommandString 中的代码被执行。异常发生在这之后的某个地方，但仍然在上下文菜单可见之前。不幸的是，这些细节对我来说意义不大：

在 explorer.exe 中的 0x00007FF9B1C4C613 (shell32.dll) 处引发异常：0xC0000005：访问冲突读取位置 0x00007FF9776D9868。发生了

堆栈跟踪：

shell32.dll!00007ff9b1c4c613()  
ExplorerFrame.dll!00007ff98d24993a()  
ExplorerFrame.dll!00007ff98d2c69a4()  
ExplorerFrame.dll!00007ff98d24de6c()  
ExplorerFrame.dll!00007ff98d251286()  
ExplorerFrame.dll!00007ff98d1fbad0()  
ExplorerFrame.dll!00007ff98d1ad5b3()  
ExplorerFrame.dll!00007ff98d180f2e()  
user32.dll!00007ff9b079ca66()  
user32.dll!00007ff9b079c34b()  
comctl32.dll!00007ff99d78b0da()  
comctl32.dll!00007ff99d78b017()  
ExplorerFrame.dll!00007ff98d187521()  
ExplorerFrame.dll!00007ff98d17d2e0()  
comctl32.dll!00007ff99d78b0da()  
comctl32.dll!00007ff99d78aef2()  
user32.dll!00007ff9b079ca66()  
user32.dll!00007ff9b079c34b()  
duser.dll!00007ff98106dff5()  
atlthunk.dll!00007ff983061208()  
user32.dll!00007ff9b079ca66()  
user32.dll!00007ff9b079c78c()  
user32.dll!00007ff9b07afa83()  
ntdll.dll!00007ff9b34833a4()  
win32u.dll!00007ff9b0071184()  
user32.dll!00007ff9b079bfbe()  
user32.dll!00007ff9b079be38()  
comctl32.dll!00007ff99d77a099()  
comctl32.dll!00007ff99d80b556()  
comctl32.dll!00007ff99d7b1302()  
user32.dll!00007ff9b079ca66()  
user32.dll!00007ff9b079c34b()  
comctl32.dll!00007ff99d78b0da()  
comctl32.dll!00007ff99d78b017()  
ExplorerFrame.dll!00007ff98d1bf33b()  
ExplorerFrame.dll!00007ff98d1bf27b()  
comctl32.dll!00007ff99d78b0da()  
comctl32.dll!00007ff99d78aef2()  
user32.dll!00007ff9b079ca66()  
user32.dll!00007ff9b079c582()  
ExplorerFrame.dll!00007ff98d1748a3()  
ExplorerFrame.dll!00007ff98d1747a9()  
ExplorerFrame.dll!00007ff98d1746f6()  
ExplorerFrame.dll!00007ff98d175a12()  
ExplorerFrame.dll!00007ff98d1870c2()  
windows.storage.dll!00007ff9af8db38c()  
windows.storage.dll!00007ff9af8db045()  
windows.storage.dll!00007ff9af8daf25()  
SHCore.dll!00007ff9b164c315()  
kernel32.dll!00007ff9b06281f4()  
ntdll.dll!00007ff9b344a251()

Answer 1

看来我解决了这个问题。我重新设计了项目的其余部分，即 IClassFactory 的实现以及 shellextension 类的 IUnknown 接口的实现，目的是了解这些“东西”在该项目中的用途。

这样做时，我发现了一些错误、未初始化的变量、强制类型转换等。我还将一些计数器从 UINT 更改为 LONG，以便我可以使用 InterlockedIncrement 而不是 ++。在那之后，问题似乎消失了。我不能再确切地说是什么错误导致了 AccessViolationException，但最后它不像我想的那样在 QueryContextMenu 方法中......