如何在 shell 环境（winapi）中获取带扩展名的文件名？答案

【问题标题】：How to get filename with extension in shell envirionment (winapi)?如何在 shell 环境（winapi）中获取带扩展名的文件名？
【发布时间】：2021-02-11 19:15:48
【问题描述】：

我有一个程序可以获取有关 Windows 回收站中文件的信息。我看到的桶访问问题的唯一非拐杖解决方案是使用 shell 环境。

我有一个使用 winapi（shell 环境）从回收站中删除单个文件（或文件夹）的代码，如下所示：

#include <iostream>

#include <shobjidl_core.h>
#include <Shlobj.h>
#include <shlwapi.h>
#include <ntquery.h>

const SHCOLUMNID SCID_RemovedFrom = { PSGUID_DISPLACED, PID_DISPLACED_FROM };
const SHCOLUMNID SCID_RemovedName = { PSGUID_STORAGE, PID_STG_NAME };

const SHCOLUMNID SCID_DateDeleted = { PSGUID_DISPLACED, PID_DISPLACED_DATE };
const SHCOLUMNID SCID_DateCreated = { PSGUID_STORAGE, PID_STG_CREATETIME };
const SHCOLUMNID SCID_DateModifed = { PSGUID_STORAGE, PID_STG_WRITETIME };
const SHCOLUMNID SCID_DateOpened = { PSGUID_STORAGE, PID_STG_ACCESSTIME };

int main() {
    CoInitializeEx(NULL, COINIT_APARTMENTTHREADED | COINIT_DISABLE_OLE1DDE);

    LPSHELLFOLDER pDesktop = NULL;
    SHGetDesktopFolder(&pDesktop);

    LPITEMIDLIST pidlRecycleBin = NULL;
    SHGetSpecialFolderLocation(NULL, CSIDL_BITBUCKET, &pidlRecycleBin);

    IShellFolder2 *pRecycleBin;
    pDesktop->BindToObject(pidlRecycleBin, NULL, IID_IShellFolder2, (LPVOID*)&pRecycleBin);

    pDesktop->Release();
    CoTaskMemFree(pidlRecycleBin);

    IEnumIDList* penumFiles;
    pRecycleBin->EnumObjects(NULL, SHCONTF_FOLDERS | SHCONTF_NONFOLDERS, &penumFiles);
    
    STRRET sret;

    IFileOperation *pfo;
    CoCreateInstance(CLSID_FileOperation, NULL, CLSCTX_ALL, IID_PPV_ARGS(&pfo));
    pfo->SetOperationFlags(FOF_NO_UI);

    LPITEMIDLIST pidl = NULL;

    BSTR bstr = NULL;
    VARIANT vt;
    SYSTEMTIME syst;

    while (penumFiles->Next(1, &pidl, NULL) != S_FALSE) {
        
        pRecycleBin->GetDisplayNameOf(pidl, SHGDN_NORMAL, &sret); // not a FULL name!!!

        StrRetToBSTR(&sret, pidl, &bstr);
        std::wcout << bstr << L' ';
        SysFreeString(bstr);

        pRecycleBin->GetDetailsEx(pidl, &SCID_DateDeleted, &vt);
        VariantTimeToSystemTime(vt.date, &syst);
        std::wcout << "\t" << syst.wHour << ":" << syst.wMinute << " " << syst.wDay << "." << syst.wMonth << "." << syst.wYear << std::endl;

        /*MARK ITEMS TO DELETE*/
        SHCreateItemWithParent(NULL, pRecycleBin, pidl, IID_IShellItem, (void**)&shi);
        pfo->DeleteItem(shi, NULL);
        shi->Release();

        CoTaskMemFree(pidl);
    }
    penumFiles->Release();
    pRecycleBin->Release();

    /*DELETE MARKED ITEMS*/
    pfo->PerformOperations();
    pfo->Release();

    //Update recycle bin icon [undocumented function]
    (void (*)())GetProcAddress(GetModuleHandle(L"shell32.dll"), "SHUpdateRecycleBinIcon")();

    CoUninitialize();
    return 0;
}

在上面的代码中，在顶部，有常量定义（SCID_RemovedFrom、SCID_RemovedName）用于通过函数GetDetailsEx获取被删除文件所在的路径和名称。但是，生成的名称并不总是包含扩展名，而只有当文件在系统中注册时，才会在文件资源管理器中显示扩展名。在其他情况下，获取的名称不带扩展名。

无论用户的设置如何，我都找不到GetDetailsEx 将返回全名（带扩展名）的常量。到目前为止，我只找到了一个拐杖：使用pRecycleBin->GetDisplayNameOf(pidl, SHGDN_FORPARSING, &sret); 来获取扩展名，但是有一个问题：我无法确定如何解释名称some.docx 和扩展名$RXZH1I6.docx: 是some.docx 的全名（如果显示扩展名）或some.docx.docx 是全名（如果隐藏扩展名）。原来这个拐杖甚至是危险的。

如何获得保证有扩展名的任何文件（“非文件夹”）的名称？

【问题讨论】：

你读过How can I get information about the items in the Recycle Bin?了吗？
@RemyLebeau 我读了好几遍。正是从这里我拿起了PSGUID_DISPLACED，这在msdn上没有提到。然而，这里使用了臭名昭著的GetDisplayNameOf，它根据用户的设置提供扩展。我需要保证延期。
问题中说明了这一点：GetDisplayNameOf 和 pRecycleBin->GetDetailsEx(pidl, &SCID_RemovedName, &vt) 都不能给我一个带有扩展名的名字。有时扩展名存在（例如对于 cpp），有时则不存在（例如对于 flac），尽管两者都是文件。
你读过Recycle Bin Forensics了吗？最坏的情况是，您可以直接解析 bin 的元数据文件以获得所需的内容。信息就在那里，因为垃圾箱需要它来恢复。
我无法重现您的问题，我回收的所有内容都以全名结束。否则，要获取项目的“扩展名”，请使用 PKEY_ItemType（适用于所有外壳项目）和/或 PKEY_FileExtension 物理文件/文件夹外壳项目

标签： c++ winapi windows-shell shell32

【解决方案1】：

这里有一些示例代码（使用 ATL 实现智能指针），显示回收站（或您想要的任何其他文件夹）中所有项目的所有属性。

您可以选择所需的属性。我已经使用已删除的 txt 文件转储了示例输出。项目的显示名称实际上取决于匹配设置，但您可以看到还有很多其他有趣的属性，例如：

System.Recycle.DeletedFrom (eq to SCID_RemovedFrom)
System.Recycle.DateDeleted（相当于 SCID_DateDeleted）
System.ItemNameDisplay（注意虚拟物品，你不会总是有一个 System.FileName)
System.ItemType（关于虚拟物品的备注，你不会总是有 System.FileExtension)

样本输出：

D:\temp\New Text Document.txt // this is the normal display name (depends on settings)
 System.ItemFolderNameDisplay = Recycle Bin
 System.ItemTypeText = Text Document
 System.ItemNameDisplay = New Text Document.txt
 System.Size = 0
 System.FileAttributes = 33
 System.DateModified = 2019/12/04:17:52:05.132
 System.DateCreated = 2019/12/04:17:52:06.000
 System.DateAccessed = 2019/12/04:17:52:06.000
 System.ItemNameDisplayWithoutExtension = $RWLK87M
 System.ContentType = text/plain
 System.Document.DateCreated = 2019/12/04:17:52:05.132
 System.Document.DateSaved = 2019/12/04:17:52:05.132
 System.Recycle.DeletedFrom = D:\temp
 System.Recycle.DateDeleted = 2021/02/16:08:18:46.000
 System.FileOwner = KILLROY\WasHere
 System.NetworkLocation = 
 System.ComputerName = KILLROY
 System.ItemPathDisplayNarrow = $RWLK87M (D:\$RECYCLE.BIN\Recycle Bin)
 System.PerceivedType = 1
 System.ItemType = .txt
 System.ParsingName = D:\$RECYCLE.BIN\S-1-5-21-2804694453-2728412037-1988799983-1001\$RWLK87M.txt
 System.SFGAOFlags = 1077936503
 System.ParsingPath = D:\$RECYCLE.BIN\S-1-5-21-2804694453-2728412037-1988799983-1001\$RWLK87M.txt
 System.FileExtension = .txt
 System.ItemDate = 2019/12/04:17:52:05.132
 System.KindText = Document
 System.FileAttributesDisplay = Read-only
 System.IsShared = 0
 System.SharedWith = 
 System.SharingStatus = 2
 System.ShareScope = 
 System.Security.EncryptionOwnersDisplay = 
 System.ItemName = $RWLK87M.txt
 System.Shell.SFGAOFlagsStrings = filesys; stream
 System.Link.TargetSFGAOFlagsStrings = 
 System.OfflineAvailability = 
 System.ZoneIdentifier = 0
 System.LastWriterPackageFamilyName = 
 System.AppZoneIdentifier = 
 System.Kind = document
 System.Security.EncryptionOwners = 
 System.ItemFolderPathDisplayNarrow = Recycle Bin (D:\$RECYCLE.BIN)
 System.FileName = New Text Document.txt
 System.Security.AllowedEnterpriseDataProtectionIdentities = 
 System.ThumbnailCacheId = 11524143073100486861
 System.VolumeId = {184CD9C9-570E-483F-9AE1-68D57270A239}
 System.Link.TargetParsingPath = 
 System.Link.TargetSFGAOFlags = 
 System.ItemFolderPathDisplay = D:\$RECYCLE.BIN\Recycle Bin
 System.ItemPathDisplay = D:\$RECYCLE.BIN\Recycle Bin\$RWLK87M.txt
 {9E5E05AC-1936-4A75-94F7-4704B8B01923} 0 = New Text Document.txt
 System.AppUserModel.ID = 
 System.AppUserModel.ParentID = 
 System.Link.TargetExtension = 
 System.OfflineStatus = 
 System.IsFolder = 0
 System.NotUserContent = 0
 System.StorageProviderAggregatedCustomStates = 
 System.SyncTransferStatusFlags = 
 System.DateImported = 2019/12/04:17:52:05.132
 System.ExpandoProperties = 
 System.FilePlaceholderStatus = 6

示例代码：

#include <iostream>
#include <shobjidl_core.h>
#include <shlobj.h>
#include <propvarutil.h>
#include <atlbase.h>
#include <atlcom.h>

#pragma comment(lib, "propsys")

int main() {
    HRESULT hr = CoInitialize(nullptr);
    {
        // get recycle bin folder
        CComPtr<IShellItem> bin;
        hr = SHCreateItemInKnownFolder(FOLDERID_RecycleBinFolder, 0, nullptr, IID_PPV_ARGS(&bin));
        if (SUCCEEDED(hr))
        {
            // enumerate items
            CComPtr<IEnumShellItems> items;
            hr = bin->BindToHandler(nullptr, BHID_EnumItems, IID_PPV_ARGS(&items));
            if (SUCCEEDED(hr))
            {
                do
                {
                    // get item
                    CComPtr<IShellItem> item;
                    hr = items->Next(1, &item, nullptr);
                    if (hr != 0)
                        break;

                    // get the display name (depends on settings)
                    CComHeapPtr<wchar_t> path;
                    item->GetDisplayName(SIGDN_NORMALDISPLAY, &path);
                    std::wcout << path.m_pData << std::endl;

                    // get item's property store
                    CComPtr<IPropertyStore> store;
                    hr = CComQIPtr<IShellItem2>(item)->GetPropertyStore(GPS_DEFAULT, IID_PPV_ARGS(&store));
                    if (SUCCEEDED(hr))
                    {
                        DWORD count = 0;
                        store->GetCount(&count);
                        for (DWORD i = 0; i < count; i++)
                        {
                            // print this property (name, value)
                            PROPERTYKEY pk;
                            hr = store->GetAt(i, &pk);
                            if (SUCCEEDED(hr))
                            {
                                // get property canonical name
                                CComHeapPtr<wchar_t> name;
                                PSGetNameFromPropertyKey(pk, &name);

                                // get property value
                                PROPVARIANT pv;
                                PropVariantInit(&pv);
                                hr = store->GetValue(pk, &pv);
                                if (SUCCEEDED(hr))
                                {
                                    CComHeapPtr<wchar_t> value;
                                    hr = PropVariantToStringAlloc(pv, &value); // propvarutil.h
                                    if (SUCCEEDED(hr))
                                    {
                                        if (!name) // unknown name
                                        {
                                            CComHeapPtr<wchar_t> fmtid;
                                            StringFromCLSID(pk.fmtid, &fmtid);
                                            std::wcout << L" " << fmtid.m_pData << L" " << pk.pid << L" = " << value.m_pData << std::endl;
                                        }
                                        else
                                        {
                                            std::wcout << L" " << name.m_pData << L" = " << value.m_pData << std::endl;
                                        }
                                    }
                                    else
                                    {
                                        // can't convert to string, print something useful
                                    }
                                }
                                PropVariantClear(&pv);
                            }
                        }
                    }
                } while (true);
            }
        }
    }
    CoUninitialize();
    return 0;
}

【讨论】：