字节数转换为KB或MB或GB

function BytesToStr(const i64Size: Int64): string;
const
  i64GB = 1024 * 1024 * 1024;
  i64MB = 1024 * 1024;
  i64KB = 1024;
begin
  if i64Size div i64GB > 0 then
    Result := Format('%.2f GB ', [i64Size / i64GB])
  else if i64Size div i64MB > 0 then
    Result := Format('%.2f MB ', [i64Size / i64MB])
  else if i64Size div i64KB > 0 then
    Result := Format('%.2f KB ', [i64Size / i64KB])
  else
    Result := IntToStr(i64Size) + ' Byte';
end;