asp.net根据日期算出天数的小例子

//计算天数
   protectedintgetDays(DateTimedate1,DateTimedate2)
   {

       intdays=0;
       if(date1.Year==date2.Year)
       {
           if(date1.Month<date2.Month)
           {
               days=(date2.Day-date1.Day)+(date2.Month-date1.Month)*30;
           }
           if(date2.Month==date1.Month)
           {
               days=date2.Day-date1.Day;
           }
       }
       else
       {
           DateTimedate3=Convert.ToDateTime(date1.Year+"-12-31");
           DateTimedate4=Convert.ToDateTime(date2.Year+"-01-01");
           intday1=0;
           if(date1.Month<date3.Month)
           {
               day1=(date3.Day-date1.Day)+(date3.Month-date1.Month)*30;
           }
           if(date3.Month==date1.Month)
           {
               day1=date3.Day-date1.Day;
           }

 

           intday2=0;
           if(date4.Month<date2.Month)
           {
               day2=(date2.Day-date4.Day)+(date2.Month-date4.Month)*30;
           }
           if(date4.Month==date2.Month)
           {
               day2=date2.Day-date4.Day;
           }

           days=day1+day2;

       }
       returndays;
   }