WeeksInAYear、WeeksInYear、DaysInAYear、DaysInAMonth、DaysInYear、DaysInMonth - 获取指定年月的周、日数

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

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
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);    //53
end;

end.