delphi文件流

var 
 FLoadsteam: TFileStream; 
 FcopySteam: TFileStream; 
 buffer: array[0..1023] of char; 
begin 
 FLoadsteam := TFileStream.Create('F:QQ34Wrox - Professional C# (C#高级编程).pdf',fmOpenRead); 
 FcopySteam := TFileStream.Create('F:QQ34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;