给程序内部菜单增加指定的explorer菜单

为了将explorer的右键菜单项的某个菜单增加到我们程序内部的菜单，我们需要做以下几件事情：

1. 获得指定文件的IShellFolder
2. 获得指定文件的IContextMenu
3. 创建菜单A，并且把IContextMenu的内容填充到菜单A
4. 查询菜单A，找到我们想要的菜单项
5. 取出我们想要的菜单项的内容，填充到我们想要真正弹出的菜单B
6. 弹出菜单B
7. 用IContextMenu响应用户对菜单的选择

代码如下:

CComPtr<IShellFolder> GetParentFolder(LPCWSTR szFolder)
{
    CComPtr<IShellFolder> pDesktop;
    SHGetDesktopFolder(&pDesktop);
    if (NULL == pDesktop)
    {
        return NULL;
    }

    ULONG pchEaten = 0;
    LPITEMIDLIST pidl = NULL;
    DWORD dwAttributes = 0;
    HRESULT hr = pDesktop->ParseDisplayName(NULL, NULL, (LPTSTR)szFolder, NULL, &pidl, NULL);
    if (S_OK != hr)
    {
        return NULL;
    }

    CComPtr<IShellFolder> pParentFolder = NULL;
    hr = pDesktop->BindToObject(pidl, NULL, IID_IShellFolder, (void**)&pParentFolder);
    if (S_OK != hr)
    {
        CoTaskMemFree(pidl);
        return NULL;
    }

    CoTaskMemFree(pidl);

    return pParentFolder;
}

std::wstring GetDirectory(LPCWSTR szFile)
{
    WCHAR szDrive[_MAX_DRIVE];
    WCHAR szDir[_MAX_DIR];
    WCHAR szFName[_MAX_FNAME];
    WCHAR szExt[_MAX_EXT];
    _wsplitpath_s(szFile, szDrive, szDir, szFName, szExt);

    std::wstring strResult = szDrive;
    strResult += szDir;
    return strResult;
}

std::wstring GetFileNameWithExt(LPCWSTR szFile)
{
    WCHAR szDrive[_MAX_DRIVE];
    WCHAR szDir[_MAX_DIR];
    WCHAR szFName[_MAX_FNAME];
    WCHAR szExt[_MAX_EXT];
    _wsplitpath_s(szFile, szDrive, szDir, szFName, szExt);

    std::wstring strResult = szFName;
    strResult += szExt;
    return strResult;
}
void qtmenutest::ShowContextMenu(const QPoint &pos) 
{
    m_pContextMenu.Release();
    QMenu contextMenu(tr("Context menu"), this);

    std::wstring strFilePath = L"d:\\1.jpg";
    CComPtr<IShellFolder> pParentFolder = GetParentFolder(GetDirectory(strFilePath.c_str()).c_str());
    if (NULL == pParentFolder)
    {
        return;
    }

    std::wstring strFile = GetFileNameWithExt(strFilePath.c_str());
    ULONG pchEaten = 0;
    LPITEMIDLIST pidl = NULL;
    DWORD dwAttributes = 0;
    HRESULT hr = pParentFolder->ParseDisplayName(WId(), NULL, (LPWSTR)strFile.c_str(), &pchEaten, &pidl, &dwAttributes);
    if (S_OK != hr)
    {
        return;
    }

    
    UINT refReversed = 0;
    hr = pParentFolder->GetUIObjectOf(WId(), 1, (LPCITEMIDLIST *)&pidl, IID_IContextMenu, &refReversed, (void **)&m_pContextMenu);
    if (S_OK != hr)
    {
        CoTaskMemFree(pidl);
        return;
    }

    HMENU hMenu = CreatePopupMenu();
    if (hMenu == NULL) {
        CoTaskMemFree(pidl);
        return;
    }

    m_pContextMenu->QueryContextMenu(hMenu, 0, 100, 200, CMF_EXPLORE | CMF_NORMAL);
    int nMenuCount = GetMenuItemCount(hMenu);
    HMENU hSubMenu = NULL;
    WCHAR szMenuText[MAX_PATH];
    for (int i = 0; i < nMenuCount; i++) {
        GetMenuStringW(hMenu, i, szMenuText, MAX_PATH, MF_BYPOSITION);
        if (wcsstr(szMenuText, L"some_ui_text")) {
            hSubMenu = GetSubMenu(hMenu, i);
            break;
        }
    }

    QMenu *subMenu = contextMenu.addMenu(QString::fromWCharArray(szMenuText));
    int nSubMenuCount = GetMenuItemCount(hSubMenu);
    for (int i = 0; i < nSubMenuCount; i++) {
        GetMenuStringW(hSubMenu, i, szMenuText, MAX_PATH, MF_BYPOSITION);
        int nCmdId = GetMenuItemID(hSubMenu, i);
        QAction *curAct = subMenu->addAction(QString::fromWCharArray(szMenuText));
        if (curAct) {
            curAct->setData(nCmdId);
        }
    }

    QAction *selAct = contextMenu.exec(mapToGlobal(pos));
    if (selAct) {
        int nSelId = selAct->data().toInt();
        if (nSelId) {
            CMINVOKECOMMANDINFO info = {0};
            info.cbSize = sizeof(CMINVOKECOMMANDINFOEX);
            info.lpVerb = MAKEINTRESOURCEA(nSelId - 100);
            m_pContextMenu->InvokeCommand(&info);
        }
    }

    DestroyMenu(hMenu);
    CoTaskMemFree(pidl);
    return;
}