Delphi DateUtils 增時函數：IncYear/IncMonth/IncDay... 完整指南

日期時間增減運算：八大 IncXxx 函數統一接口

DateUtils 提供 IncYear/Month/Week/Day/Hour/Minute/Second/MilliSecond 八個函數，統一簽名 function IncXxx(const AValue: TDateTime; const ANumberOfXxx: Int64 = 1): TDateTime，支援正負增量。

函數列表

IncYear        IncMonth       IncWeek        IncDay
IncHour        IncMinute      IncSecond      IncMilliSecond

測試代碼與結果

uses DateUtils;
procedure TForm1.FormCreate(Sender: TObject);
var t1, t2: TDateTime;
begin
  t1 := StrToDateTime('2011-1-1 1:1:1');

  t2 := IncYear(t1);       ShowMessage(DateTimeToStr(t2));  {2012-1-1 1:01:01}
  t2 := IncYear(t1, 3);    ShowMessage(DateTimeToStr(t2));  {2014-1-1 1:01:01}
  t2 := IncMonth(t1);      ShowMessage(DateTimeToStr(t2));  {2011-2-1 1:01:01}
  t2 := IncWeek(t1);       ShowMessage(DateTimeToStr(t2));  {2011-1-8 1:01:01}
  t2 := IncDay(t1);        ShowMessage(DateTimeToStr(t2));  {2011-1-2 1:01:01}
  t2 := IncHour(t1);       ShowMessage(DateTimeToStr(t2));  {2011-1-1 2:01:01}
  t2 := IncMinute(t1);     ShowMessage(DateTimeToStr(t2));  {2011-1-1 1:02:01}
  t2 := IncSecond(t1);     ShowMessage(DateTimeToStr(t2));  {2011-1-1 1:01:02}
  t2 := IncMilliSecond(t1);
  ShowMessage(FormatDateTime('yyyy-m-d h:n:s:zzz', t2));    {2011-1-1 1:01:01:001}
end;

特性：

• 自動處理月份天數差異、閏年、跨月/跨年邊界
• ANumberOfXxx 可為負數實現減法
• 返回新 TDateTime，不修改原值
• 毫秒級精度（IncMilliSecond）