看的一些源码

function TryEncodeTime(Hour, Min, Sec, MSec: Word; out Time: TDateTime): Boolean;
begin
  Result := False;
  if (Hour < HoursPerDay) and (Min < MinsPerHour) and (Sec < SecsPerMin) and (MSec < MSecsPerSec) then
  begin
    Time := (Hour * (MinsPerHour * SecsPerMin * MSecsPerSec) +
             Min * (SecsPerMin * MSecsPerSec) +
             Sec * MSecsPerSec +
             MSec) / MSecsPerDay;
    Result := True;
  end;
end;

Delphi中时间的表示方法。