将文件复制到剪贴板，然后将它们粘贴到其原始文件夹中不起作用

Question

我遇到了一个令人费解的情况。我在 Delphi 中使用以下代码将文件列表复制到剪贴板；

procedure TfMain.CopyFilesToClipboard(FileList: string);
const
  C_UNABLE_TO_ALLOCATE_MEMORY = 'Unable to allocate memory.';
  C_UNABLE_TO_ACCESS_MEMORY = 'Unable to access allocated memory.';
var
  DropFiles: PDropFiles;
  hGlobal: THandle;
  iLen: Integer;
begin
  iLen := Length(FileList);
  hGlobal := GlobalAlloc(GMEM_SHARE or GMEM_MOVEABLE or
  GMEM_ZEROINIT, SizeOf(TDropFiles) + ((iLen + 2) * SizeOf(Char)));
  if (hGlobal = 0) then
    raise Exception.Create(C_UNABLE_TO_ALLOCATE_MEMORY);
  try DropFiles := GlobalLock(hGlobal);
    if (DropFiles = nil) then raise Exception.Create(C_UNABLE_TO_ACCESS_MEMORY);
    try
      DropFiles^.pFiles := SizeOf(TDropFiles);
      DropFiles^.fWide := True;
      if FileList <> '' then
        Move(FileList[1], (PByte(DropFiles) + SizeOf(TDropFiles))^,
      iLen * SizeOf(Char));
    finally
      GlobalUnlock(hGlobal);
    end;
    Clipboard.SetAsHandle(CF_HDROP, hGlobal);
  except
    GlobalFree(hGlobal);
  end;
end;

（这似乎是互联网上流行的一段代码）

使用我的应用程序，将文件复制到剪贴板后，我可以使用 Windows 资源管理器将它们粘贴到所有其他文件夹中，但文件最初来自的文件夹除外！我期待它的行为就像一个普通的 Windows 副本（即在粘贴时它应该创建一个后缀为“-Copy”的文件），但这似乎不起作用。有什么线索吗？

Answer 1

当唯一可用的剪贴板格式为 CF_HDROP 时，我无法让 Windows 资源管理器粘贴到源文件夹中。但是，如果文件名是在 IDataObject 中提供的，则可以正常工作。

如果所有文件都来自同一个源文件夹，您可以检索源文件夹的 IShellFolder 并在其中查询各个文件的子 PIDL，然后使用 IShellFolder.GetUIObjectOf() 获取代表的 IDataObject文件。然后使用OleSetClipboard() 将该对象放在剪贴板上。例如：

uses
  System.Classes, Winapi.Windows, Winapi.ActiveX, Winapi.Shlobj, Winapi.ShellAPI, System.Win.ComObj;

procedure CopyFilesToClipboard(const Folder: string; FileNames: TStrings);
var
  SF: IShellFolder;
  PidlFolder: PItemIDList;
  PidlChildren: array of PItemIDList;
  Eaten: UINT;
  Attrs: DWORD;
  Obj: IDataObject;
  I: Integer;
begin
  if (Folder = '') or (FileNames = nil) or (FileNames.Count = 0) then Exit;
  OleCheck(SHParseDisplayName(PChar(Folder), nil, PidlFolder, 0, Attrs));
  try
    OleCheck(SHBindToObject(nil, PidlFolder, nil, IShellFolder, Pointer(SF)));
  finally
    CoTaskMemFree(PidlFolder);
  end;
  SetLength(PidlChildren, FileNames.Count);
  for I := Low(PidlChildren) to High(PidlChildren) do
    PidlChildren[i] := nil;
  try
    for I := 0 to FileNames.Count-1 do
      OleCheck(SF.ParseDisplayName(0, nil, PChar(FileNames[i]), Eaten, PidlChildren[i], Attrs));
    OleCheck(SF.GetUIObjectOf(0, FileNames.Count, PIdlChildren[0], IDataObject, nil, obj));
  finally
    for I := Low(PidlChildren) to High(PidlChildren) do
    begin
      if PidlChildren[i] <> nil then
        CoTaskMemFree(PidlChildren[i]);
    end;
  end;
  OleCheck(OleSetClipboard(obj));
  OleCheck(OleFlushClipboard);
end;

更新：如果文件在不同的源文件夹，可以使用CFSTR_SHELLIDLIST格式：

uses
  System.Classes, System.SysUtils, Winapi.Windows, Winapi.ActiveX, Winapi.Shlobj, Winapi.ShellAPI, System.Win.ComObj, Vcl.Clipbrd;

{$POINTERMATH ON}

function HIDA_GetPIDLFolder(pida: PIDA): LPITEMIDLIST;
begin
  Result := LPITEMIDLIST(LPBYTE(pida) + pida.aoffset[0]);
end;

function HIDA_GetPIDLItem(pida: PIDA; idx: Integer): LPITEMIDLIST;
begin
  Result := LPITEMIDLIST(LPBYTE(pida) + (PUINT(@pida.aoffset[0])+(1+idx))^);
end;

var
  CF_SHELLIDLIST: UINT = 0;

type
  CidaPidlInfo = record
    Pidl: PItemIDList;
    PidlOffset: UINT;
    PidlSize: UINT;
  end;

procedure CopyFilesToClipboard(FileNames: TStrings);
var
  PidlInfo: array of CidaPidlInfo;
  Attrs, AllocSize: DWORD;
  gmem: THandle;
  ida: PIDA;
  I: Integer;
begin
  if (FileNames = nil) or (FileNames.Count = 0) or (CF_SHELLIDLIST = 0) then Exit;
  SetLength(PidlInfo, FileNames.Count);
  for I := Low(PidlInfo) to High(PidlInfo) do
    PidlInfo[I].Pidl := nil;
  try
    AllocSize := SizeOf(CIDA)+(SizeOf(UINT)*FileNames.Count)+SizeOf(Word);
    for I := 0 to FileNames.Count-1 do
    begin
      OleCheck(SHParseDisplayName(PChar(FileNames[I]), nil, PidlInfo[I].Pidl, 0, Attrs));
      PidlInfo[I].PidlOffset := AllocSize;
      PidlInfo[I].PidlSize := ILGetSize(PidlInfo[I].Pidl);
      Inc(AllocSize, PidlInfo[I].PidlSize);
    end;
    gmem := GlobalAlloc(GMEM_MOVEABLE, AllocSize);
    if gmem = 0 then RaiseLastOSError;
    try
      ida := PIDA(GlobalLock(gmem));
      if ida = nil then RaiseLastOSError;
      try
        ida.cidl := FileNames.Count;
        ida.aoffset[0] := SizeOf(CIDA)+(SizeOf(UINT)*FileNames.Count);
        HIDA_GetPIDLFolder(ida).mkid.cb := 0;
        for I := 0 to FileNames.Count-1 do
        begin
          ida.aoffset[1+I] := PidlInfo[I].PidlOffset;
          Move(PidlInfo[I].Pidl^, HIDA_GetPIDLItem(ida, I)^, PidlInfo[I].PidlSize);
        end;
      finally
        GlobalUnlock(gmem);
      end;
      Clipboard.SetAsHandle(CF_SHELLIDLIST, gmem);
    except
      GlobalFree(gmem);
      raise;
    end;
  finally
    for I := Low(PidlInfo) to High(PidlInfo) do
      CoTaskMemFree(PidlInfo[I].Pidl);
  end;
end;

initialization
  CF_SHELLIDLIST := RegisterClipboardFormat(CFSTR_SHELLIDLIST);

或者：

procedure CopyFilesToClipboard(FileNames: TStrings);
var
  Pidls: array of PItemIdList;
  Attrs: DWORD;
  I: Integer;
  obj: IDataObject;
begin
  if (FileNames = nil) or (FileNames.Count = 0) then Exit;
  SetLength(Pidls, FileNames.Count);
  for I := Low(Pidls) to High(Pidls) do
    Pidls[I] := nil;
  try
    for I := 0 to FileNames.Count-1 do
      OleCheck(SHParseDisplayName(PChar(FileNames[I]), nil, Pidls[I], 0, Attrs));
    OleCheck(CIDLData_CreateFromIDArray(nil, FileNames.Count, PItemIDList(Pidls), obj));
  finally
    for I := Low(Pidls) to High(Pidls) do
      CoTaskMemFree(Pidls[I]);
  end;
  OleCheck(OleSetClipboard(obj));
  OleCheck(OleFlushClipboard);
end;

但是，我发现 Windows 资源管理器有时但并不总是允许将 CFSTR_SHELLIDLIST 粘贴到引用文件的源文件夹中。我不知道阻止 Windows 资源管理器粘贴的标准是什么。也许是某种权限问题？

你应该听取微软的建议：

Handling Shell Data Transfer Scenarios

包括尽可能多的格式，你可以支持。您通常不知道数据对象将被删除到哪里。这种做法提高了数据对象包含放置目标可以接受的格式的几率。