C#中计算两个时间的差，得到月份

              string beginDate="2007-1-1";

               string endDate="2008-12-31";

//合同期限(月)=合同结束日期-合同开始日期    

            TimeSpan dt1 = new TimeSpan(Convert.ToDateTime(beginDate).Ticks);
            TimeSpan dt2 = new TimeSpan(Convert.ToDateTime(endDate).Ticks);
            TimeSpan dt = dt2.Subtract(dt1).Duration();
            //string contractTerm = dt.Days.ToString();
            int ICount = dt.Days / 30;
            string contractTerm = ICount.ToString();