windows - Delphi中的剪贴板操作

Question

本地工作站:Win 7

终端服务器:Win 2008服务器

Outlook:2003 在本地工作站上运行。

我正在尝试实现将 Outlook 消息从本地工作站复制和粘贴到终端服务器。

使用下面的代码，我可以将文件从本地工作站复制并粘贴到服务器...

TmyMemoryStream = class(TMemoryStream);

...

procedure TmyMemoryStream.LoadFromIStream(AStream : IStream);
var
  iPos : Int64;
  aStreamStat : TStatStg;
  oOLEStream: TOleStream;
begin
  AStream.Seek(0, STREAM_SEEK_SET, iPos);
  AStream.Stat(aStreamStat, STATFLAG_NONAME);
  oOLEStream := TOLEStream.Create(AStream);
  try
    Self.Clear;
    Self.Position := 0;
    Self.CopyFrom( oOLEStream, aStreamStat.cbSize );
    Self.Position := 0;
  finally
    oOLEStream.Free;
  end;
end;

...但是当我尝试复制和粘贴 Outlook 邮件时，流大小 (aStreamStat.cbSize) 为 0。我能够获取邮件主题(文件名)，但是无法读取流内容。

我的代码有什么问题？

完整的单元代码:

unit Unit1;

interface
uses
  dialogs,
  Windows, ComCtrls, ActiveX, ShlObj, ComObj, StdCtrls, AxCtrls,
  SysUtils, Controls, ShellAPI, Classes, Forms;

type

  {****************************************************************************}

  TMyDataObjectHandler = class;

  PFileDescriptorArray = Array of TFileDescriptor;

  {****************************************************************************}

  TMyDataObjectHandler = class(TObject)
  strict private
    CF_FileContents            : UINT;
    CF_FileGroupDescriptorA    : UINT;
    CF_FileGroupDescriptorW    : UINT;
    CF_FileDescriptor          : UINT;
    FDirectory                 : string;
    function  _CanCopyFiles(const ADataObject : IDataObject) : boolean;
    function  _DoCopyFiles(const ADataObject : IDataObject) : HResult;
    //function  _ExtractFileNameWithoutExt(const FileName: string): string;
    function  _CopyFiles(AFileNames: TStringList): HResult;
    procedure _GetFileNames(AGroup: PDropFiles; var AFileNames: TStringList);
    procedure _ProcessAnsiFiles(ADataObject: IDataObject; AGroup: PFileGroupDescriptorA);
    function  _ProcessDropFiles(ADataObject: IDataObject; AGroup: PDropFiles): HResult;
    procedure _ProcessFileContents(ADataObject: IDataObject; Index: UINT; AFileName: string; AFileSize : Cardinal);
    function  _ProcessStorageMedium(ADataObject: IDataObject; AMedium: STGMEDIUM; AFilename: string; AFileSize : Cardinal): HResult;
    function  _ProcessStreamMedium(ADataObject: IDataObject; AMedium: STGMEDIUM; AFileName: String; AFileSize : Cardinal): HResult;
    procedure _ProcessUnicodeFiles(ADataObject: IDataObject; AGroup: PFileGroupDescriptorW );
    function  _CanCopyFile(AFileName: string): boolean;
  public
    constructor Create; reintroduce;
    destructor Destroy; override;
    function  CanCopyFiles(const ADataObject : IDataObject; const ADirectory : string) : boolean;
    procedure CopyFiles(const ADataObject : IDataObject; const ADirectory : string);
  end;

  {****************************************************************************}

  TMyMemoryStream = class( TMemoryStream )
  public
    procedure LoadFromIStream(AStream : IStream; AFileSize : Cardinal);
    function GetIStream : IStream;
  end;

  {****************************************************************************}

implementation

{------------------------------------------------------------------------------}

{ TMyDataObjectHandler }

function TMyDataObjectHandler.CanCopyFiles(const ADataObject : IDataObject; const ADirectory : string): boolean;
begin
  Result := IsDirectoryWriteable( ADirectory);
  if Result then
  begin
    Result := _CanCopyFiles(ADataObject);
  end;
end;

{------------------------------------------------------------------------------}

constructor TMyDataObjectHandler.Create;
begin
  inherited Create;
  CF_FileContents         := $8000 OR RegisterClipboardFormat(CFSTR_FILECONTENTS)     AND $7FFF;
  CF_FileGroupDescriptorA := $8000 OR RegisterClipboardFormat(CFSTR_FILEDESCRIPTORA)  AND $7FFF;
  CF_FileGroupDescriptorW := $8000 OR RegisterClipboardFormat(CFSTR_FILEDESCRIPTORW)  AND $7FFF;
  CF_FileDescriptor       := $8000 OR RegisterClipboardFormat(CFSTR_FILEDESCRIPTOR)   AND $7FFF;
end;

{------------------------------------------------------------------------------}

destructor TMyDataObjectHandler.Destroy;
begin
  //
  inherited;
end;

{------------------------------------------------------------------------------}

procedure TMyDataObjectHandler.CopyFiles(const ADataObject : IDataObject; const ADirectory : string);
begin
  FDirectory := ADirectory;
  _DoCopyFiles(ADataObject);
end;

{------------------------------------------------------------------------------}

function TMyDataObjectHandler._CanCopyFiles(const ADataObject : IDataObject) : boolean;
var
  eFORMATETC : IEnumFORMATETC;
  OLEFormat  : TFormatEtc;
  iFetched   : Integer;
begin
  Result := false;
  if Succeeded(ADataObject.EnumFormatEtc(DATADIR_GET, eFormatETC)) then
  begin
    if Succeeded(eFormatETC.Reset) then
    begin
      while(eFORMATETC.Next(1, OLEFormat, @iFetched) = S_OK) and (not Result) do
      begin
        Result := ( OLEFormat.cfFormat = CF_FileGroupDescriptorW )
                  or
                  ( OLEFormat.cfFormat = CF_FileGroupDescriptorA )
                  or
                  ( OLEFormat.cfFormat = CF_HDROP );
      end;
    end;
  end;
end;

{------------------------------------------------------------------------------}

function  TMyDataObjectHandler._CanCopyFile( AFileName : string ) : boolean;
begin
  Result := not FileExists( ExpandUNCFileName(FDirectory + ExtractFileName(AFileName)) );
end;

{------------------------------------------------------------------------------}

function  TMyDataObjectHandler._CopyFiles(AFileNames : TStringList) : HResult;
var
  i: Integer;
begin
  Result := S_OK;
  i := 0;
  while(i < AFileNames.Count) do
  begin
    if _CanCopyFile(AFileNames[i]) then
    begin
      Copyfile( Application.MainForm.Handle, PChar(AFileNames[i]), PChar(FDirectory + ExtractFileName(AFileNames[i])), false );
    end;
    inc(i);
  end;
end;

{------------------------------------------------------------------------------}

procedure TMyDataObjectHandler._GetFileNames(AGroup: PDropFiles; var AFileNames : TStringList);
var
  sFilename : PAnsiChar;
  s         : string;
begin
  sFilename := PAnsiChar(AGroup) + AGroup^.pFiles;
  while (sFilename^ <> #0) do
  begin
    if (AGroup^.fWide) then
    begin
      s := PWideChar(sFilename);
      Inc(sFilename, (Length(s) + 1) * 2);
    end
    else
    begin
      s := PWideChar(sFilename);
      Inc(sFilename, Length(s) + 1);
    end;
    AFileNames.Add(s);
  end;
end;

{------------------------------------------------------------------------------}

function TMyDataObjectHandler._ProcessDropFiles(ADataObject: IDataObject; AGroup: PDropFiles) : HResult;
var
  sFiles    : TStringList;
begin
  Result := S_OK;
  sFiles := TStringList.Create;
  try
    _GetFileNames( AGroup, sFiles );
    if (sFiles.Count > 0) then
    begin
      Result := _CopyFiles( sFiles );
    end;
  finally
    sFiles.Free;
  end;
end;

{------------------------------------------------------------------------------}

function TMyDataObjectHandler._ProcessStorageMedium(ADataObject: IDataObject; AMedium: STGMEDIUM; AFilename : string; AFileSize : Cardinal) : HResult;
var
  StorageInterface     : IStorage;
  FileStorageInterface : IStorage;
  sGUID                : PGuid;
  iCreateFlags         : integer;
begin
  Result := S_OK;
  if _CanCopyFile(AFileName) then
  begin
    sGUID := nil;
    StorageInterface := IStorage(AMedium.stg);
    iCreateFlags := STGM_CREATE OR STGM_READWRITE OR STGM_SHARE_EXCLUSIVE;
    Result := StgCreateDocfile(PWideChar(ExpandUNCFileName(FDirectory + AFilename)), iCreateFlags, 0, FileStorageInterface);
    if Succeeded(Result) then
    begin
      Result := StorageInterface.CopyTo(0, sGUID, nil, FileStorageInterface);
      if Succeeded(Result) then
      begin
        Result := FileStorageInterface.Commit(0);
      end;
      FileStorageInterface := nil;
    end;
    StorageInterface := nil;
  end;
end;

{------------------------------------------------------------------------------}

function TMyDataObjectHandler._ProcessStreamMedium(ADataObject: IDataObject; AMedium: STGMEDIUM; AFileName : String; AFileSize : Cardinal) : HResult;
var
  Stream : IStream;
  myStream: TMyMemoryStream;
begin
  Result := S_OK;
  if _CanCopyFile(AFileName) then
  begin
    Stream := ISTREAM(AMedium.stm);
    if (Stream <> nil) then
    begin
      myStream := TMyMemoryStream.Create;
      try
        myStream.LoadFromIStream(Stream, AFileSize);
        myStream.SaveToFile(ExpandUNCFileName(FDirectory + AFileName));
      finally
        myStream.Free;
      end;
    end;
  end;
end;

{------------------------------------------------------------------------------}

procedure TMyDataObjectHandler._ProcessFileContents(ADataObject: IDataObject; Index: UINT; AFileName : string; AFileSize : Cardinal);
var
  Fetc: FORMATETC;
  Medium: STGMEDIUM;
begin
  Fetc.cfFormat := CF_FILECONTENTS;
  Fetc.ptd := nil;
  Fetc.dwAspect := DVASPECT_CONTENT;
  Fetc.lindex := Index;
  Fetc.tymed := TYMED_HGLOBAL or TYMED_ISTREAM or TYMED_ISTORAGE;
  if SUCCEEDED(ADataObject.GetData(Fetc, Medium)) then
  begin
    try
      case Medium.tymed of
        TYMED_HGLOBAL  : ;
        TYMED_ISTREAM  : _ProcessStreamMedium(ADataObject, Medium, AFileName, AFileSize);
        TYMED_ISTORAGE : _ProcessStorageMedium(ADataObject, Medium, AFileName, AFileSize);
        else ;
      end;
    finally
      ReleaseStgMedium(Medium);
    end;
  end;
end;

{------------------------------------------------------------------------------}

procedure TMyDataObjectHandler._ProcessAnsiFiles(ADataObject: IDataObject; AGroup: PFileGroupDescriptorA);
var
  I         : UINT;
  sFileName : AnsiString;
  iSize     : Cardinal;
begin
  for I := 0 to AGroup^.cItems-1 do
  begin
    sFileName := AGroup^.fgd[I].cFileName;
    if (AGroup^.fgd[I].dwFlags and FD_FILESIZE) = FD_FILESIZE then
    begin
      iSize := (AGroup^.fgd[I].nFileSizeLow and $7FFFFFFF);
    end
    else
    begin
      iSize := 0;
    end;
    _ProcessFileContents(ADataObject, I, string(sFileName), iSize);
  end;
end;

{------------------------------------------------------------------------------}

procedure TMyDataObjectHandler._ProcessUnicodeFiles(ADataObject : IDataObject;
                                                  AGroup      : PFileGroupDescriptorW);
var
  I: UINT;
  sFileName: WideString;
  iSize: Cardinal;
begin
  for I := 0 to AGroup^.cItems-1 do
  begin
    sFileName := AGroup^.fgd[I].cFileName;
    if (AGroup^.fgd[I].dwFlags and FD_FILESIZE) = FD_FILESIZE then
    begin
      iSize := (AGroup^.fgd[I].nFileSizeLow and $7FFFFFFF);
    end
    else
    begin
      iSize := 0;
    end;
    _ProcessFileContents(ADataObject, I, sFileName, iSize);
  end;
end;


{------------------------------------------------------------------------------}

function TMyDataObjectHandler._DoCopyFiles(const ADataObject : IDataObject) : HResult;
var
  Fetc       : FORMATETC;
  Medium     : STGMEDIUM;
  Enum       : IEnumFORMATETC;
  Group      : Pointer;
begin
  Result := ADataObject.EnumFormatEtc(DATADIR_GET, Enum);
  if FAILED(Result) then
    Exit;
  while (true) do
  begin
    Result := (Enum.Next(1, Fetc, nil));
    if (Result = S_OK) then
    begin
      if (Fetc.cfFormat = CF_FILEGROUPDESCRIPTORA)   or
         (Fetc.cfFormat = CF_FILEGROUPDESCRIPTORW)  or
         (Fetc.cfFormat = CF_HDROP) then
      begin
        Result := ADataObject.GetData(Fetc, Medium);
        if FAILED(Result) then
          Exit;
        try
          if (Medium.tymed = TYMED_HGLOBAL) then
          begin
            Group := GlobalLock(Medium.hGlobal);
            try
              if Fetc.cfFormat = CF_FILEGROUPDESCRIPTORW then
              begin
                _ProcessUnicodeFiles(ADataObject, PFileGroupDescriptorW(Group));
                break;
              end
              else if Fetc.cfFormat = CF_FILEGROUPDESCRIPTORA then
              begin
                _ProcessAnsiFiles(ADataObject, PFileGroupDescriptorA(Group));
                break;
              end
              else if Fetc.cfFormat = CF_HDROP then
              begin
                _ProcessDropFiles(ADataObject, PDropFiles(Group));
                break;
              end;
            finally
              GlobalUnlock(Medium.hGlobal);
            end;
          end;
        finally
          ReleaseStgMedium(Medium);
        end;
      end;
    end
    else
      break;
  end;
end;

{------------------------------------------------------------------------------}

//function TMyDataObjectHandler._ExtractFileNameWithoutExt(const FileName: string): string;
//begin
//  Result := ChangeFileExt(ExtractFileName(FileName), EmptyStr);
//end;

{------------------------------------------------------------------------------}

{ TMyMemoryStream }

function TMyMemoryStream.GetIStream: IStream;
var
  oStreamAdapter : TStreamAdapter;
  tPos           : Int64;
begin
  oStreamAdapter := TStreamAdapter.Create(Self);
  oStreamAdapter.Seek(0, 0, tPos);
  Result := oStreamAdapter as IStream;
end;

procedure TMyMemoryStream.LoadFromIStream(AStream : IStream; AFileSize : Cardinal);
var
  iPos : Int64;
  aStreamStat         : TStatStg;
  oOLEStream: TOleStream;
  HR: Int64;
begin
  oOLEStream := TOLEStream.Create(AStream);
  try
    Self.Clear;
    Self.Position := 0;
    try
      HR := Self.CopyFrom( oOLEStream, 0 );
    except
    on E : Exception do
    begin
      showMessage(E.ClassName + ' ' + E.Message);
    end;
    end;
    Self.Position := 0;
  finally
    oOLEStream.Free;
  end;
end;

end.

Answer 1

问题是，对于 CF_FILEDESCRIPTORW 或 CF_FILEDESCRIPTORA，Windows 提供的 IStream 不支持 Seek 函数，也不支持正确的 StreamStat.cbSize 字段。因此有必要从 TFileDescriptor 记录的 nFileSizeLow 和 nFileSizeHigh 字段中获取流大小。也不可能使用 TStream.CopyFrom(oOLEStream, 0) 因为在零秒参数的情况下 TStream 调用不支持的 Seek 函数，因此您有 EOleSysError 异常。