Delphi 时间操作函数

DateUtils.StartOfTheMonth(Now) //本月第一天
DateUtils.EndOfTheMonth(Now)   //本月最后一天

DateUtils.YearsBetween()
DateUtils.MonthsBetween()
DateUtils.DaysBetween();
DateUtils.HoursBetween();
DateUtils.MinutesBetween();
DateUtils.SecondsBetween();
DateUtils.MilliSecondsBetween()

DateUtils.IncYear();
DateUtils.IncMonth();
DateUtils.IncWeek();
DateUtils.IncDay();
DateUtils.IncHour();
DateUtils.IncMinute();
DateUtils.IncSecond();
DateUtils.IncMilliSecond();

//两个时间差是否在 xx 个年、月，周，天，小时，分钟，秒，毫秒内
DateUtils.WithinPastYears();
DateUtils.WithinPastMonths();
DateUtils.WithinPastWeek();
DateUtils.WithinPastDays();
DateUtils.WithinPastHours();
DateUtils.WithinPastMinutes();
DateUtils.WithinPastSeconds();
DateUtils.WithinPastMilliSeconds();

procedure TForm1.FormCreate(Sender: TObject);
var
t1,t2: TDateTime;
b: Boolean;
begin
t1 := StrToDateTime('2009-5-20 11:22:33');
t2 := StrToDateTime('2009-5-21 11:22:33');
 
{两个时间差是否在 24 年内}
b := WithinPastYears(t1, t2, 24); //True
 
{两个时间差是否在 24 个月内}
b := WithinPastMonths(t1, t2, 24); //True
 
{两个时间差是否在 24 个周内}
b := WithinPastWeeks(t1, t2, 24); //True
 
{两个时间差是否在 24 天内}
b := WithinPastDays(t1, t2, 24); //True
 
{两个时间差是否在 24 个小时内}
b := WithinPastHours(t1, t2, 24); //True
 
{两个时间差是否在 24 分钟内}
b := WithinPastMinutes(t1, t2, 24); //False
 
{两个时间差是否在 24 秒内}
b := WithinPastSeconds(t1, t2, 24); //False
 
{两个时间差是否在 24 毫秒内}
b := WithinPastMilliSeconds(t1, t2, 24); //False
 
// ShowMessage(BoolToStr(b, True));
end;