1、变量声明：
var
h1,m1,s1,h2,m2,s2,h3,m3,s3:integer;
time1,time2:string;
ptime1,ptime2:pchar;
timelist1,timelist2:tStringList;
2、在计时开始按钮单击事件中，获得当前时间，并分割出时、分、秒。
time1:=timetostr(time); //获得第一个当前时间，并且赋值给time1变量
ptime1:=pchar(time1); //把time1的字符串以pchar形式赋值给ptime1
timelist1:=TStringList.Create; //建立一个字符串列表。
ExtractStrings([':'], [' '], ptime1, timelist1); //分割获得的时间钟的时、分、秒
h1:=strtoint(timelist1[0]); //把时赋值给h1
m1:=strtoint(timelist1[1]); //把分赋值给m1
s1:=strtoint(timelist1[2]); //把秒赋值给s1
timer1.Interval:=1000; //设置timer周期为1000(一秒钟触发一次,设计时，timer的周期为0）
procedure Tstudyfrm.Timer1Timer(Sender: TObject);
begin
time2:=timetostr(time); //获得下一个个当前时间
ptime2:=pchar(time2);
timelist2:=TStringList.Create;
ExtractStrings([':'], [' '], ptime2, timelist2); //分割
h2:=strtoint(timelist2[0]); //赋值
m2:=strtoint(timelist2[1]);
s2:=strtoint(timelist2[2]);
if s2>=s1 then //秒够减 //开始计算。。。。
begin
s3:=s2-s1;
if m2>=m1 then //分够减
begin
m3:=m2-m1;
if h2>=h1 then //时够减
begin
h3:=h2-h1;
end
else //时不够减
begin
h3:=h2+24-h1;
end;
end
else //分不够减
begin
m3:=m2+60-m1;
if h2>0 then
begin
h2:=h2-1;
if h2>=h1 then h3:=h2-h1 else h3:=h2+24-h1;
end
else
begin
h3:=h2+23-h1;
end;
end;
end
else //秒不够减
begin
s3:=s2+60-s1;
if m2>0 then
begin
m2:=m2-1;
if m2>=m1 then
begin
m3:=m2-m1;
if h2>=h1 then h3:=h2-h1 else h3:=h2+24-h1;
end
else
begin
m3:=m2+60-m1;
if h2>0 then
begin
h2:=h2-1;
if h2>=h1 then h3:=h2-h1 else h3:=h2+24-h1;
end
else
begin
h3:=23-h1;
end;
end;
end
else
begin
m3:=59-m1;
if h2>0 then
begin
h2:=h2-1;
if h2>=h1 then h3:=h2-h1 else
begin
h3:=h2+24-h1;
end;
end
else
begin
h3:=23-h1;
end;
end;
end;
label3.Caption:=inttostr(h3)+'时'+inttostr(m3)+'分'+inttostr(s3)+'秒'; //用label控件显示时间。
end;
![GridView终极用法(一)[图]](data:image/gif;base64,R0lGODlhAQABAIAAAP///wAAACwAAAAAAQABAAACAkQBADs=)