使用WindowsShell获取文件缩略图

HRESULT KThumbnailGetter::GetShellThumbnailImage(LPCWSTR pszPath, HBITMAP* pThumbnail){    HRESULT hr;    *pThumbnail = NULL;    LPITEMIDLIST pidlItems = NULL, pidlURL = NULL, pidlWorkDir;    WCHAR szBasePath[MAX_PATH], szFileName[MAX_PATH];    WCHAR* p;    wcscpy(szBasePath, pszPath);    p = wcsrchr(szBasePath, L'\\');    if (p) *(p + 1) = L'\0';    wcscpy(szFileName, pszPath + (p - szBasePath) + 1);    do    {        CComPtr<IShellFolder> psfDesktop;        hr = SHGetDesktopFolder(&psfDesktop);        if (FAILED(hr)) break;        CComPtr<IShellFolder> psfWorkDir;        DWORD dwAttribs = SFGAO_COMPRESSED;        ULONG cbEaten;        hr = psfDesktop->ParseDisplayName(NULL, NULL, szBasePath, &cbEaten, &pidlWorkDir, NULL);        if (FAILED(hr)) break;        hr = psfDesktop->BindToObject(pidlWorkDir, NULL, IID_IShellFolder, (LPVOID*)&psfWorkDir);        if (FAILED(hr)) break;        // 获取文件的PIDL        hr = psfWorkDir->ParseDisplayName(NULL, NULL, szFileName, NULL, &pidlURL, NULL);        if (FAILED(hr)) break;        // 查询缩略图          CComPtr<IExtractImage> peiURL;        hr = psfWorkDir->GetUIObjectOf(NULL, 1, (LPCITEMIDLIST*)&pidlURL, IID_IExtractImage, NULL, (LPVOID*)&peiURL);        if (FAILED(hr)) break;        // 定义缩略图属性        SIZE size = { 256, 256 };        DWORD dwPriority = 0, dwFlags = IEIFLAG_ASPECT;        WCHAR pszImagePath[MAX_PATH];        hr = peiURL->GetLocation(pszImagePath, MAX_PATH, &dwPriority, &size, 16, &dwFlags);        if (FAILED(hr)) break;        // 提取缩略图          hr = peiURL->Extract(pThumbnail);        if (FAILED(hr)) break;        break;    } while (0);    // 释放资源     if (pidlWorkDir) CoTaskMemFree(pidlWorkDir);    if (pidlURL) CoTaskMemFree(pidlURL);    return hr;}