IsSameDay、IsToday - 判断是不是同一天、判断是不是今天

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,t3,t4: TDateTime;
  b: Boolean;
begin
  t1 := StrToDateTime('2009-1-21');
  t2 := StrToDateTime('2009-1-21');
  t3 := StrToDateTime('2009-5-21');
  t4 := Now;

  {判断是不是同一天}
  b := IsSameDay(t1, t2); //True
  b := IsSameDay(t1, t3); //False

  {判断给定时间和当前时间是不是同一天}
  b := IsToday(t1); //False
  b := IsToDay(t4); //True

//  ShowMessage(BoolToStr(b, True));
end;

end.