use TimeSpan classusing System;DateTime dt1 = new DateTime(2002,11,1);
DateTime dt2 = new DateTime(2002,12,1);TimeSpan ts = dt2 - dt1;double d = ts.TotalDays;
DateTime dt2 = new DateTime(2002,12,1);TimeSpan ts = dt2 - dt1;double d = ts.TotalDays;
//span is +1 hour看TimeSpan和DateTime的运算符的参考