日期比较问题

Question

两个日期
2010-7-21 00:00:00
2010-7-22 00:00:00怎么做能准备比较这两个日期之间相差的天数或者小时呢 ？用
TimeSpan ts = endDate.Subtract(startDate);
int days = ts.Days;
int hours = ts.Hours;days 算出来是 1
hours算出来时 0  

Answer 1

TotalDays:返回TimeSpan值表示的天数。 
TotalHours:返回TimeSpan值表示的小时数。 

Answer 2

DateTime startDate = DateTime.Parse("2010-7-21 00:00:00");
DateTime endDate = DateTime.Parse("2010-7-22 00:00:00");
TimeSpan ts = endDate.Subtract(startDate);
double days = ts.TotalDays;
double hours = ts.TotalHours;

Answer 3

public enum EnumDateCompare
    {
        year = 1,
        month = 2,
        day = 3,
        hour = 4,
        minute = 5,
        second = 6
    }    /// <summary>
    /// 日期比较函数
    /// </summary>
    /// <param name="howtocompare"></param>
    /// <param name="startDate"></param>
    /// <param name="endDate"></param>
    /// <returns></returns>
    public 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;
    }
封装一下用起来比较方便 如：
DateDiff(EnumDateCompare.hour,starttime,stoptime)

Answer 4

DateTime startDate = DateTime.Parse("2010-7-21 00:00:00");
DateTime endDate = DateTime.Parse("2010-7-22 00:00:00");
double days = (endDate - startDate).TotalDays;
double hours = (endDate - startDate).TotalHours;