C#里面比较时间大小三种方法

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();