C#比较时间大小

1、比较时间大小的实验
     string st1="12:13";
     string st2="14:14";
     DateTime dt1=Convert.ToDateTime(st1);
     DateTime dt2=Convert.ToDateTime(st2);
     DateTime dt3=DateTime.Now;
     if(DateTime.Compare(dt1,dt2)>0)
      msg.Text=st1+">"+st2;
     else
      msg.Text=st1+"<"+st2;
     msg.Text+="\r\n"+dt1.ToString();
     if(DateTime.Compare(dt1,dt3)>0)
      msg.Text+="\r\n"+st1+">"+dt3.ToString();
     else
      msg.Text+="\r\n"+st1+"<"+dt3.ToString();

2、计算两个时间差值的函数，返回时间差的绝对值：
          private string DateDiff(DateTime DateTime1,DateTime DateTime2)
          {
              string dateDiff=null;
              try
              {
                  TimeSpan ts1=new    TimeSpan(DateTime1.Ticks);
                  TimeSpan ts2=new    TimeSpan(DateTime2.Ticks);
                  TimeSpan ts=ts1.Subtract(ts2).Duration();
                  dateDiff=ts.Days.ToString()+"天"
                          +ts.Hours.ToString()+"小时"
                          +ts.Minutes.ToString()+"分钟"
                          +ts.Seconds.ToString()+"秒";
              }
              catch
              {

              }
              return dateDiff;
          }

3、实现计算DateTime1－36天＝DateTime2的功能

     TimeSpan ts=new TimeSpan(40,0,0,0);
     DateTime dt2=DateTime.Now.Subtract(ts);
     msg.Text=DateTime.Now.ToString()+"-"+ts.Days.ToString()+"天\r\n";
     msg.Text+=dt2.ToString();