WithinPastYears、WithinPastMonths、WithinPastWeeks、WithinPastDays ... 判断两个时间差是否在一个指定范围内
DateUtils.WithinPastYears();
DateUtils.WithinPastMonths();
DateUtils.WithinPastWeeks();
DateUtils.WithinPastDays();
DateUtils.WithinPastHours();
DateUtils.WithinPastMinutes();
DateUtils.WithinPastSeconds();
DateUtils.WithinPastMilliSeconds(); 
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unit Unit1;

interface

uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls;

type
TForm1 = class(TForm)
procedure FormCreate(Sender: TObject);
end;

var
Form1: TForm1;

implementation

{$R *.dfm}

uses DateUtils;

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;

end.