unit exacttimer;
interface
uses
  windows, messages, sysutils, classes, graphics, controls, forms, dialogs,
  stdctrls, extctrls, mmsystem;
type
  tform1 = class(tform)
    button1: tbutton;
    button2: tbutton;
    timer1: ttimer;
    Edit1: TEdit;
    Edit2: TEdit;
    Edit3: TEdit;
    Label1: TLabel;
    Label2: TLabel;
    Label3: TLabel;
    procedure formcreate(sender: tobject);
    procedure button1click(sender: tobject);
    procedure timer1timer(sender: tobject);
    procedure button2click(sender: tobject);
  private
    { private declarations }
  public
    { public declarations }
  end;
var
  form1: tform1;
  acttime1, acttime2: cardinal;
  smmcount, stimercount, spcount: single;
  htimeid: integer;
  iten: integer;
  protimecallback: tfntimecallback;
procedure timeproc(utimerid, umessage: uint; dwuser, dw1, dw2: dword) stdcall;
procedure proendcount;

implementation
uses XMconsts;
{$R *.dfm}
//timesetevent的回調函數

procedure proendcount;
begin
  acttime2 := gettickcount - acttime1; //獲得總共運行的毫秒數
  form1.button2.enabled := false;
  form1.button1.enabled := true;
  form1.timer1.enabled := false;
  smmcount := 60;
  stimercount := 60;
  spcount := -1;
  timekillevent(htimeid);
end;

procedure timeproc(utimerid, umessage: uint; dwuser, dw1, dw2: dword) stdcall;
begin
  form1.edit2.text := floattostr(smmcount);
  smmcount := smmcount - 0.01;
end;

procedure tform1.formcreate(sender: tobject);
begin
  Self.Caption := GetAppTitle(44, True);
  button1.caption := '開始倒計時';
  button2.caption := '結束倒計時';
  button2.enabled := false;
  button1.enabled := true;
  timer1.enabled := false;
  smmcount := 60;
  stimercount := 60;
  spcount := 60;
end;

procedure tform1.button1click(sender: tobject);
var
  lgtick1, lgtick2, lgper: tlargeinteger;
  ftemp: single;
begin
  button2.enabled := true;
  button1.enabled := false;
  timer1.enabled := true;
  timer1.interval := 10; //設置Timer1的時間間隔為10毫秒
  protimecallback := timeproc; //設置回調函數
  htimeid := timesetevent(10, 0, protimecallback, 1, 1);
  acttime1 := gettickcount; //獲得當前的Windows已運行毫秒數
  queryperformancefrequency(lgper);
  //獲得系統的高性能頻率計數器在一秒內的震動次數
  ftemp := lgper / 1000; //獲得系統的高性能頻率計數器在一毫秒內的震動次數
  iten := trunc(ftemp * 10);
  queryperformancecounter(lgtick1); //獲得初始時的當前系統頻率計數器的震蕩次數
  lgtick2 := lgtick1;
  spcount := 60;
  while spcount > 0 do
  begin
    queryperformancecounter(lgtick2);
    if lgtick2 - lgtick1 > iten then
    begin //如果時鐘震動次數超過10毫秒的次數則刷新edit3的顯示
      lgtick1 := lgtick2;
      spcount := spcount - 0.01; //60秒減去10毫秒
      edit3.text := floattostr(spcount);
      application.processmessages; //出讓CPU
    end;
  end;
end;

procedure tform1.timer1timer(sender: tobject);
begin
  edit1.text := floattostr(stimercount);
  stimercount := stimercount - 0.01;
end;

procedure tform1.button2click(sender: tobject);
begin
  proendcount;
  //顯示從開始記數到記數實際經過的時間
  showmessage('實際經過時間' + inttostr(acttime2) + '毫秒');
end;
end.