nbsp;   button1: tbutton;
    button2: tbutton;
    timer1: ttimer;
    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

{$r *.dfm}

//timesetevent的回调函数

procedure proendcount;
begin
  acttime2:=gettickcount-acttime1;
  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
  button1.caption :=''开始倒计时'';
  button2.caption :=''结束倒计时'';
  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;
  protimecallback:=timeproc;
  htimeid:=timesetevent(10,0,protimecallback,1,1);
  acttime1:=gettickcount;
  //获得系统的高性能频率计数器在一毫秒内的震动次数
  queryperformancefrequency(lgper);
  ftemp:=lgper/1000;
  iten:=trunc(ftemp*10);
  queryperformancecounter(lgtick1);
  lgtick2:=lgtick1;
  spcount:=60;
  while spcount>0 do begin
   queryperformancecounter(lgtick2);
    //如果时钟震动次数超过10毫秒的次数则刷新edit3的显示
    if lgtick2 - lgtick1 > iten then begin
            lgtick1 := lgtick2;
            spcount := spcount - 0.01;
            edit3.text := floattostr(spcount);
      &nb