如何获得 window shell文件夹缩略图

这个问题关系到 shell接口编程部分，一个比较令人纠结的问题时，不管操作那个部分的文件夹，都要从shell文件系统的root节点(Desktop)开始操作，直到找到你要的节点位置。概因树形结构表达有关。

不说了，直接上代码吧:

LPITEMIDLIST pidlItems = NULL, pidlURL = NULL, pidlWorkDir = NULL; 

    ULONG   ulParseLen = 0;

    HRESULT hr; 

    TCHAR pszPath[MAX_PATH*2]; 

    DWORD dwPriority = 0, dwFlags = IEIFLAG_SCREEN; 

    SIZE size = { dwWidth, dwHeight }; 

    IExtractImage* peiURL = NULL;    // interface is used to request a thumbnail image from a Shell folder

    IShellFolder* psfDesktop = NULL; 

    IShellFolder* psfWorkDir = NULL; 

    IMalloc*              pMalloc = NULL;

    TString TempTumbnail = GetMediaLibraryDefaultDir() + _T( "MLThumbnail.jpg" );

    CImage myImage;

    TString wsDir,wsFile,wsTempFile; 

    BOOL bComInit = TRUE;

    hr = CoInitialize( NULL );

    hr = SHGetMalloc( &pMalloc );

    hr = SHGetDesktopFolder(&psfDesktop); 

    wsDir = LocalFile;

    wsDir.erase(wsDir.find_last_of(_T( '\\' )) + 1, wsDir.length());

    wsFile = LocalFile;

    wsFile.erase(0, wsFile.find_last_of(_T( '\\' )) + 1);

    // get working directory 

    TCHAR m_wsBuffer[255];

    _tcscpy_s(m_wsBuffer,wsDir.c_str());

    // ParseDisplayName:Translates a file object's or folder's display name into an item identifier list.

    hr = psfDesktop->ParseDisplayName(NULL, NULL, m_wsBuffer, &ulParseLen, &pidlWorkDir, NULL); 

    hr = psfDesktop->BindToObject(pidlWorkDir, NULL, IID_IShellFolder, (LPVOID*)&psfWorkDir); 

    psfDesktop->Release(); 

    psfDesktop = NULL; 

    pMalloc->Free(pidlWorkDir); 

    pidlWorkDir = NULL; 

    // retrieve link information 

    _tcscpy_s(m_wsBuffer,wsFile.c_str()); 

    hr = psfWorkDir->ParseDisplayName(NULL, NULL, m_wsBuffer, &ulParseLen, &pidlURL, NULL); 

    // query IExtractImage 

    hr = psfWorkDir->GetUIObjectOf(NULL, 1, (LPCITEMIDLIST*)&pidlURL, IID_IExtractImage, NULL, (LPVOID*)&peiURL); 

    // define thumbnail properties 

    hr = peiURL->GetLocation(pszPath, MAX_PATH*2, &dwPriority, &size, 16, &dwFlags); 

    // generate thumbnail 

    HBITMAP  hThumbnail= NULL;

    hr = peiURL->Extract(&hThumbnail); 

    // clean-up IExtractImage 

    peiURL->Release(); 

    peiURL = NULL; 

    myImage.Attach(hThumbnail);

    myImage.Save(TempTumbnail.c_str());

    // free allocated structures 

    if (peiURL != NULL) peiURL->Release(); 

    if (pidlURL != NULL) pMalloc->Free(pidlURL); 

    if (pidlWorkDir != NULL) pMalloc->Free(pidlWorkDir); 

    if (psfDesktop != NULL) psfDesktop->Release(); 

    if (psfWorkDir != NULL) psfWorkDir->Release();