Question

我正在尝试使用c ++编写上下文菜单处理程序。我希望处理程序可以处理所有文件和所有文件夹，也可以处理资源管理器左窗格中的文件和文件夹。我从一个CodeProject项目开始，该项目旨在适应我的需求。我是从here获得的。

直到现在，除了资源管理器左窗格中的文件夹之外，其他所有东西似乎都可以正常工作。那里我得到一个AccessViolationException。在右键单击和上下文菜单的显示之间发生例外。我删除了不同功能中的代码，直到再次起作用，看来问题出在QueryContextMenu方法上。

有人知道我在做什么错吗？

这是我当前有效的代码（因为没有添加任何项目，所以很明显）：

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中添加一项，则资源管理器的左窗格将引发异常，而右窗格中的文件和文件夹会很好地工作。我尝试了在互联网上找到的以下两个版本，但都存在相同的问题：

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
-uMenuIndex = 3
-uidFirstCmd = 148
-uidLastCmd = 32762
-uFlags = 1044

异常详细信息。

QueryContextMenu和GetCommandString中的代码被执行。异常发生在此之后但仍在上下文菜单可见之前。不幸的是，细节对我而言并不重要：

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

Stacktrace：

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

看来我已经解决了问题。我重新设计了该项目的其余部分，即IClassFactory的实现以及shellextension类的IUnknown接口的实现，目的是了解这些“内容”在该项目中的用途。

这样做的时候，我发现了一些Bug，未初始化的变量，转换为错误的类型等。我还将一些计数器从UINT更改为LONG，以便可以使用InterlockedIncrement而不是++。之后，问题似乎消失了。我不能确切地说出是什么错误导致了AccessViolationException，但是最后它并没有出现在我所认为的QueryContextMenu方法中...

资源管理器左侧面板中的ContextMenu处理程序

1 个答案: