delphi CopyFileProgressBar 拷贝文件显示进度条

CopyFileProgressBar(pwidechar(ListBox1.Items.Strings[I]),pwidechar(NewDir+'\'+ExtractFileName(ListBox1.Items.Strings[I])));

procedure CopyFileProgressBar(getPath,setPath:string);

var

  getStream,setStream: TFileStream;

  num, n: Integer;

  buf: PByte;

  BufSize,block: Integer;

begin

  if not FileExists(getPath) then

  begin

   // ShowMessage('源文件不存在');

   // Exit;

  end;

  getStream := TFileStream.Create(getPath, fmOpenRead or fmShareExclusive);

  setStream := TFileStream.Create(setPath, fmCreate);

  num := getStream.Size;

  setStream.Size := num;

  getStream.Position := 0;

  setStream.Position := 0;

  BufSize := num;

  block := BufSize div 100;

  GetMem(buf, BufSize);

  form1.ProgressBar1.Max := 100;

  form1.ProgressBar1.Min := 0;

  form1.ProgressBar1.Position := 0;

  while num <> 0 do

  begin

    Application.ProcessMessages;

    n := block;

    if n > num then n := num;

    getStream.ReadBuffer(buf^, n);

    setStream.WriteBuffer(buf^, n);

    form1.ProgressBar1.Position := Trunc((1 - num / BufSize) * 100);

    Dec(num, n);

  end;

  FreeMem(buf, BufSize);

  getStream.Free;

  setStream.Free;

  //ShowMessage('复制完毕');

  form1.ProgressBar1.Position := 0;

end;