您可以使用 IStream 和 TStreamAdapter 。这是一个快速的例子（在D2007和XE2中测试）：

You can do this using IStream and TStreamAdapter. Here's a quick example (tested in D2007 and XE2):

uses
  ActiveX;

procedure TForm1.DoSomething;
var
  MemStream: TMemoryStream;
  ExchangeStream: IStream;
begin
  MemStream := TMemoryFile.Create;
  try
    MemStream.LoadFromFile('C:\Test\SomeFile.txt');
    MemStream.Position := 0;
    ExchangeStream := TStreamAdapter.Create(MemStream) as IStream;
    // Pass ExchangeStream to C++ DLL here, and do whatever else
  finally
    MemStream.Free;
  end;
end;

以防万一，如果你需要去另一种方式（收到一个来自C / C ++的IStream ），您可以使用 TOleStream 从 IStream 获取到Delphi TStream 。

Just in case, if you need to go the other way (receiving an IStream from C/C++), you can use TOleStream to get from that IStream to a Delphi TStream.