DateUtils.DaysInYear();DateUtils.DaysInMonth();DateUtils.DaysInAYear();DateUtils.DaysInAMonth();DateUtils.WeeksInYear();DateUtils.WeeksInAYear();

unit Unit1;interfaceuses  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  dt: TDateTime;  w: Word;begin  dt := StrToDateTime('2009-5-20 11:22:33');  {指定日期所在年的总天数}  w := DaysInYear(dt);        //365  {指定日期所在月的总天数}  w := DaysInMonth(dt);       //31  {指定年的总天数}  w := DaysInAYear(2009);     //365  {指定年、指定月的总天数}  w := DaysInAMonth(2009, 5); //31  {指定日期所在年的总周数}  w := WeeksInYear(dt);       //53  {指定年的总周数}  w := WeeksInAYear(2009);    //53end;end.