我們在編寫ASP.net程序時，經常需要計算兩個日期之間的間隔，如計算兩個日期之間相差的年數、月數、天數、小時數、分鐘，秒等，下面的源代碼就給出了具體的實現方法。

#region 在asp.net中怎么樣計算兩個日期相差的年、月份、日期、小時、分鐘 、秒等

public enum EnumDateCompare
{
        year =1,
        month =2,
        day =3,
        hour =4,
        minute =5,
        second =6
}
public static double DateDiff(EnumDateCompare howtocompare, System.DateTime startDate, System.DateTime endDate)
{ 
        double diff=0; 
        System.TimeSpan TS = new System.TimeSpan(endDate.Ticks-startDate.Ticks);

        switch (howtocompare) 
        { 
                case EnumDateCompare.year: 
                        diff = Convert.ToDouble(TS.TotalDays/365); 
                        break; 
                case EnumDateCompare.month: 
                        diff = Convert.ToDouble((TS.TotalDays/365)*12); 
                        break; 
                case EnumDateCompare.day:
                        diff = Convert.ToDouble(TS.TotalDays); 
                        break; 
                case EnumDateCompare.hour: 
                        diff = Convert.ToDouble(TS.TotalHours); 
                        break; 
                case EnumDateCompare.minute: 
                        diff = Convert.ToDouble(TS.TotalMinutes); 
                        break; 
                case EnumDateCompare.second: 
                        diff = Convert.ToDouble(TS.TotalSeconds); 
                        break; 
        }
        return diff;
}

#endregion

// 調用

// DateTime a=Convert.ToDateTime("2005-09-03 20:15");

// DateTime b=Convert.ToDateTime("2005-09-04 09:09 ");

// double d=Bll.Common.DateDiff(Bll.Common.EnumDateCompare.day,a,b);

// Response.Write(d.ToString("f0"));//四舍五入