delphi文件流

var  FLoadsteam: TFileStream;  FcopySteam: TFileStream;  buffer: array[0..1023] of char; begin  FLoadsteam := TFileStream.Create('F:\QQ\034\Wrox - Professional C# (C#高级编程).pdf',fmOpenRead);  FcopySteam := TFileStream.Create('F:\QQ\034\复制文件(C#高级编程).pdf',fmCreate);  ProgressBar1.Max := FLoadsteam.Size;  ProgressBar1.Position := 0;  while FLoadsteam.Position < FLoadsteam.Size do  begin    FLoadsteam.Read(buffer,1024);    FcopySteam.WriteBuffer(buffer,1024);    ProgressBar1.Position := FLoadsteam.Position;  end;  FcopySteam.Free;  FLoadsteam.Free; end;