How to enumerate files on a specific folder using Windows shell apis?

Question

Im trying to enumerate all files on a given path and also get their properties.

On my implementation below, i dont understand whats happening, it looks like it somehow is using the computer desktop path instead of the path on folderPath

at hr = pItem->GetDisplayName(SIGDN_FILESYSPATH, &displayName); it shows:

C:\Users\Lilo\Desktop\file.txt instead of: C:\Users\Lilo\Documents\file.txt

file.txt is on the documents folder not on the desktop

and consequently both SHGetPropertyStoreFromIDList and SHGetPropertyStoreFromParsingName fails with HRESULT_FROM_WIN32(ERROR_FILE_NOT_FOUND) : The system cannot find the file specified.

#include <windows.h>
#include <iostream>
#include <shlobj.h>
#include <atlcomcli.h>

inline void enumFiles(const std::wstring& folderPath)
{
    CoInitialize(NULL);

    HRESULT hr;
    CComPtr<IShellItem>   pFolderItem = NULL;
    CComPtr<IShellFolder> pFolder     = NULL;

    hr = SHCreateItemFromParsingName(folderPath.c_str(), NULL, IID_PPV_ARGS(&pFolderItem));
    if (FAILED(hr))
    {
        std::cout << "SHCreateItemFromParsingName failed with HRESULT:" << hr;
        CoUninitialize();
        return;
    }
    
    hr = pFolderItem->BindToHandler(NULL, BHID_SFObject, IID_PPV_ARGS(&pFolder));
    if (FAILED(hr))
    {
        std::cout << "BindToHandler failed with HRESULT:" << hr;
        CoUninitialize();
        return;
    }
  
    CComPtr<IEnumIDList> pEnum = NULL;
    hr = pFolder->EnumObjects(NULL, SHCONTF_FOLDERS | SHCONTF_NONFOLDERS, &pEnum);
    if (FAILED(hr))
    {
        std::cout << "EnumObjects failed with HRESULT:" << hr;
        CoUninitialize();
        return;
    }

    ITEMIDLIST* pidl = NULL;
    ULONG fetched;

    while (pEnum->Next(1, &pidl, &fetched) == S_OK)
    {
        CComPtr<IShellItem> pItem;
        hr = SHCreateItemFromIDList(pidl, IID_PPV_ARGS(&pItem));
        if (FAILED(hr))
        {
            std::cout << "SHCreateItemFromIDList failed with HRESULT:" << hr;
            CoTaskMemFree(pidl);
            continue;
        }

        LPWSTR displayName;
        hr = pItem->GetDisplayName(SIGDN_FILESYSPATH, &displayName);
        if (SUCCEEDED(hr))
            CoTaskMemFree(displayName);

        CComPtr<IPropertyStore> pPropertyStore;
        GETPROPERTYSTOREFLAGS flags = GPS_DEFAULT;
        hr = SHGetPropertyStoreFromIDList(pidl, flags, IID_PPV_ARGS(&pPropertyStore));
        //hr = SHGetPropertyStoreFromParsingName(displayName, NULL, GPS_DEFAULT, IID_PPV_ARGS(&pPropertyStore));
        CoTaskMemFree(pidl);
        if (FAILED(hr))
        {
            std::cout << "SHGetPropertyStoreFromIDList failed with HRESULT:" << hr;
            continue;
        }
    }

    CoUninitialize();
}

int main(int argc, char* argv[])
{
    enumFiles(L"C:\\Users\\Lilo\\Documents");
}

Answer 1

You can keep on using IShellItem and friends (IEnumShellItems) all along, IShellFolder is the underlying folder interface that's not easy to use, something like this (error-checks ommited):

void enumFiles(const std::wstring& folderPath)
{
    CComPtr<IShellItem> folder;
    SHCreateItemFromParsingName(folderPath.c_str(), nullptr, IID_PPV_ARGS(&folder));

    // create a bind context to define what we want to enumerate
    CComPtr<IPropertyBag> bag;
    PSCreateMemoryPropertyStore(IID_PPV_ARGS(&bag));

    CComPtr<IBindCtx> ctx;
    CreateBindCtx(0, &ctx);
    ctx->RegisterObjectParam((LPOLESTR)STR_PROPERTYBAG_PARAM, bag);
    auto flags = CComVariant(SHCONTF_FOLDERS | SHCONTF_NONFOLDERS);
    bag->Write(STR_ENUM_ITEMS_FLAGS, &flags);

    CComPtr<IEnumShellItems> items;
    folder->BindToHandler(ctx, BHID_EnumItems, IID_PPV_ARGS(&items));

    do
    {
        CComPtr<IShellItem> item;
        if (items->Next(1, &item, nullptr) != S_OK)
            break;

        CComHeapPtr<wchar_t> displayName;
        item->GetDisplayName(SIGDN_FILESYSPATH, &displayName);

        std::wcout << displayName.m_pData << std::endl;

        CComPtr<IPropertyStore> store;
        if (FAILED(item->BindToHandler(nullptr, BHID_PropertyStore, IID_PPV_ARGS(&store))))
        {
          CComPtr<IPropertyStoreFactory> factory;
          item->BindToHandler(nullptr, BHID_PropertyStore, IID_PPV_ARGS(&factory));

          factory->GetPropertyStore(GPS_BESTEFFORT, nullptr, IID_PPV_ARGS(&store));
        }

        // etc.

    } while (true);
}

int main(int argc, char* argv[])
{
    CoInitialize(NULL);
    {
        enumFiles(L"C:\\Users\\Lilo\\Documents");
    }
    CoUninitialize();
    return 0;
}

See here for more on the possible bind contexts.

PS 1: don't call CoInitalize in a library code, just call it once per process/thread.

PS 2: ATL has CComHeapPtr for smart memory pointer.