DateUtils.IsPM - 判断时间是否是下午
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;
b1,b2: Boolean;
begin
t1 := EncodeDateTime(2009, 5, 21, 11, 22, 33, 999);
t2 := EncodeDateTime(2009, 5, 21, 12, 22, 33, 999);

b1 := IsPM(t1); //False;
b2 := IsPM(t2); //True;

ShowMessage(BoolToStr(b1, True));
ShowMessage(BoolToStr(b2, True));
end;

end.