如何在 windows 7 上用 C++ 创建虚拟文件夹的快捷方式？

Question

我使用的平台是windows 7. 我需要为windows 上的虚拟文件夹创建快捷方式 7. 我使用 windows 7 SDK 示例在计算机下创建一个虚拟文件夹：

示例项目名为 ExplorerDataProvider，它定义了 IShellFolder class:

的 CLSID

// add classes supported by this module here
const CLASS_OBJECT_INIT c_rgClassObjectInit[] =
{
{ &CLSID_FolderViewImpl,            CFolderViewImplFolder_CreateInstance },
{ &CLSID_FolderViewImplContextMenu,CFolderViewImplContextMenu_CreateInstance },
};

CFolderViewImplFolder_CreateInstance 的定义是：

HRESULT CFolderViewImplFolder_CreateInstance(REFIID riid, void **ppv)
{
*ppv = NULL;
CFolderViewImplFolder* pFolderViewImplShellFolder = new (std::nothrow) CFolderViewImplFolder(0);
HRESULT hr = pFolderViewImplShellFolder ? S_OK : E_OUTOFMEMORY;
if (SUCCEEDED(hr))
{
    hr = pFolderViewImplShellFolder->QueryInterface(riid, ppv);
    pFolderViewImplShellFolder->Release();
}
return hr;
}

并且 CFolderViewImplFolder 实现 IShellFolder2 amd IPersistFolder2。我在这里找到了一个类似的代码，用于为打印机创建快捷方式： https://www.codeproject.com/Articles/596642/Creating-a-shortcut-programmatically-in-Cplusplus 并在 https://msdn.microsoft.com/en-us/library/aa969393.aspx#Shellink_Item_Identifiers

获得 IShellFolder 的 class 标识符后，您可以调用 CoCreateInstance 函数来检索接口的地址。然后就可以调用接口枚举文件夹中的对象，并获取要查找的对象的项标识地址。最后，您可以在对 IShellLink::SetIDList 成员函数的调用中使用该地址来创建对象的快捷方式。

我修改了

hr = SHGetMalloc(&pMalloc);
hr = SHGetDesktopFolder( &pDesktopFolder );
hr = SHGetSpecialFolderLocation( NULL, CSIDL_PRINTERS, &netItemIdLst );
hr = pDesktopFolder->BindToObject( netItemIdLst, NULL, IID_IShellFolder, (void **)&pPrinterFolder );

至

// testFolder is the CLSID for the virtual folder implementation
hr = CoCreateInstance(testFolder, NULL, CLSCTX_INPROC_SERVER, IID_IShellFolder, (LPVOID*)&pVirtualFolder);

或

hr = CoCreateInstance(testFolder, NULL, CLSCTX_INPROC_SERVER, IID_IShellFolder2, (LPVOID*)&pVirtualFolder);

但是 pVirtualFolder 仍然是 NULL，它打印出 "cannot find the corresponding interface".

我用的时候CoCreateInstance有什么问题吗？或者我不应该使用这个解决方案？有任何示例代码吗？

Answer 1

要创建快捷方式，您可以使用 official documentation. Here is a sample code that creates a shortcut for a children of "This PC" (aka: ComputerFolder)

int main()
{
    CoInitialize(NULL);
    // I've used my Apple's iCloud as an example (name is in french)
    // it's a virtual folder, a shell namespace extension
    HRESULT hr = CreateComputerChildShortCut(L"Photos iCloud", L"c:\temp\my icloud");
    printf("hr:0x%08X\n", hr);
    CoUninitialize();
    return 0;
}

HRESULT CreateComputerChildShortCut(LPWSTR childDisplayName, LPWSTR path)
{
    // get My Computer folder's ShellItem (there are other ways for this...)
    CComPtr<IShellItem> folder;
    HRESULT hr = SHCreateItemInKnownFolder(FOLDERID_ComputerFolder, 0, NULL, IID_PPV_ARGS(&folder));
    if (FAILED(hr)) return hr;

    // enumerate children
    CComPtr<IEnumShellItems> items;
    hr = folder->BindToHandler(NULL, BHID_EnumItems, IID_PPV_ARGS(&items));
    if (FAILED(hr)) return hr;

    for (CComPtr<IShellItem> item; items->Next(1, &item, NULL) == S_OK; item.Release())
    {
        // get parsing path (if's often useful)
        CComHeapPtr<wchar_t> parsingPath;
        item->GetDisplayName(SIGDN_DESKTOPABSOLUTEPARSING, &parsingPath);
        wprintf(L"Path: %s\n", parsingPath);

        // get display name
        CComHeapPtr<wchar_t> displayName;
        item->GetDisplayName(SIGDN_NORMALDISPLAY, &displayName);
        wprintf(L" Name: %s\n", displayName);

        if (!lstrcmpi(childDisplayName, displayName))
        {
            // get pidl
            // it's the unambiguous way of referencing a shell thing
            CComHeapPtr<ITEMIDLIST> pidl;
            hr = SHGetIDListFromObject(item, &pidl);
            if (FAILED(hr)) return hr;

            // create an instance of the standard Shell's folder shortcut creator
            CComPtr<IShellLink> link;
            hr = link.CoCreateInstance(CLSID_FolderShortcut);
            if (FAILED(hr)) return hr;

            // just use the pidl
            hr = link->SetIDList(pidl);
            if (FAILED(hr)) return hr;

            CComPtr<IPersistFile> file;
            hr = link->QueryInterface(&file);
            if (FAILED(hr)) return hr;

            // save the shortcut (we could also change other IShellLink parameters)
            hr = file->Save(path, FALSE);
            if (FAILED(hr)) return hr;
            break;
        }
    }
    return S_OK;
}

当然，如果您知道绝对解析路径或绝对pidl，则无需枚举任何内容，这只是为了演示目的。

如何在 windows 7 上用 C++ 创建虚拟文件夹的快捷方式？

How to create shortcut for virtual folder in C++ on windows 7?

c++

shortcut

windows-shell

clsid

shell-namespace-extension