常见日期方法荟萃

一.如何获得当月有多少天 int  m = System.DateTime.DaysInMonth(System.DateTime.Now.Year,System.DateTime.Now.Month); 二.日期型格式处理通用方法 1.在webconfig中配置如下 < add  key ="ShortDatePattern"  value ="MM-dd-yyyy"   /> < add  key ="LongDatePattern"  value ="dddd-MMMM dd-yyyy"   /> < add  key ="ShortTimePattern"  value ="hh:mm tt"   /> < add  key ="LongTimePattern"  value ="hh:mm tt"   /> 2.在global.asax中 protected   void  Application_BeginRequest(Object sender, EventArgs e) {Thread currentThread = Thread.CurrentThread;CultureInfo cul = currentThread.CurrentCulture.Clone() as CultureInfo;cul.DateTimeFormat.ShortDatePattern= BLLFacade.Common.GetShortDatePattern();cul.DateTimeFormat.LongDatePattern= BLLFacade.Common.GetLongDatePattern();cul.DateTimeFormat.ShortTimePattern= BLLFacade.Common.GetShortTimePattern();cul.DateTimeFormat.LongTimePattern= BLLFacade.Common.GetLongTimePattern();currentThread.CurrentCulture = cul;} 3.在业务逻辑层中 public   static   string  GetShortDatePattern() {return System.Configuration.ConfigurationSettings.AppSettings["ShortDatePattern"];} public   static   string  GetLongDatePattern() {return System.Configuration.ConfigurationSettings.AppSettings["LongDatePattern"];} public   static   string  GetShortTimePattern() {return System.Configuration.ConfigurationSettings.AppSettings["ShortTimePattern"];} public   static   string  GetLongTimePattern() {return System.Configuration.ConfigurationSettings.AppSettings["LongTimePattern"];} 4.然后在其他地方正常调用就可以了，如果需要修改格式只需要修改webconfig中的，且可以保证整个系统中的所有格式都是一致的 三.在asp.net中怎么样计算两个日期相差的年、月份、日期、小时、分钟 、妙等 在asp.net中怎么样计算两个日期相差的年、月份、日期、小时、分钟 、妙等 #region 在asp.net中怎么样计算两个日期相差的年、月份、日期、小时、分钟 、妙等//        调用//        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        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 四.获取某月的实际工作日(即不包括周六日) // 调用 // int days =getDays(System.DateTime.Now)); private   int  getDays(System.DateTime date1) {    int m=System.DateTime.DaysInMonth(date1.Year,date1.Month);    int mm=0;    for(int i=1;i<=m;i++)    {        System.DateTime date=Convert.ToDateTime(date1.Year+"-"+date1.Month+"-"+i);        switch (date.DayOfWeek)        {            case System.DayOfWeek.Monday:            case System.DayOfWeek.Thursday:            case System.DayOfWeek.Tuesday:            case System.DayOfWeek.Wednesday:            case System.DayOfWeek.Friday:                mm=mm+1;                break;        }                    }    return mm;} 五.获得任意两日期之间的有效工作日(不包括周六日) 获得任意两日期之间的有效工作日(不包括周六日) #region 获得任意两日期之间的有效工作日(不包括周六日)        //调用        //DateTime date1=Convert.ToDateTime("2005-10-20");        //DateTime date2=Convert.ToDateTime("2005-11-01");        //int days =getDays(date1,date2);        private int getDays(System.DateTime date1,System.DateTime date2)        {            string m=DateDiff(EnumDateCompare.day,date1,date2).ToString("f0");                        int mm=0;            for(int i=0;i<=Convert.ToInt32(m);i++)            {                System.DateTime date=Convert.ToDateTime(date1.AddDays(i));                switch (date.DayOfWeek)                {                    case System.DayOfWeek.Monday:                    case System.DayOfWeek.Thursday:                    case System.DayOfWeek.Tuesday:                    case System.DayOfWeek.Wednesday:                    case System.DayOfWeek.Friday:                        mm=mm+1;                        break;                }                            }            return mm;        }        #endregion 六.格式输出 格式输出 #region 格式输出        private void Page_Load(object sender, System.EventArgs e)        {            System.Globalization.DateTimeFormatInfo myDTFI = new System.Globalization.CultureInfo( "en-US", false ).DateTimeFormat;//中国用zh-cn            DateTime myDT =System.DateTime.Now;            Response.Write(myDT.ToString("f"));            /**//**//**//*            This code produces the following output.            FORMAT  en-US EXAMPLE            CHAR    VALUE OF ASSOCIATED PROPERTY, IF ANY              d     1/3/2002                    M/d/yyyy (ShortDatePattern)              D     Thursday, January 03, 2002                    dddd, MMMM dd, yyyy (LongDatePattern)              f     Thursday, January 03, 2002 12:00 AM              F     Thursday, January 03, 2002 12:00:00 AM                    dddd, MMMM dd, yyyy h:mm:ss tt (FullDateTimePattern)              g     1/3/2002 12:00 AM              G     1/3/2002 12:00:00 AM              m     January 03                    MMMM dd (MonthDayPattern)              M     January 03                    MMMM dd (MonthDayPattern)              r     Thu, 03 Jan 2002 00:00:00 GMT                    ddd, dd MMM yyyy HH':'mm':'ss 'GMT' (RFC1123Pattern)              R     Thu, 03 Jan 2002 00:00:00 GMT                    ddd, dd MMM yyyy HH':'mm':'ss 'GMT' (RFC1123Pattern)              s     2002-01-03T00:00:00                    yyyy'-'MM'-'dd'T'HH':'mm':'ss (SortableDateTimePattern)              t     12:00 AM                    h:mm tt (ShortTimePattern)              T     12:00:00 AM                    h:mm:ss tt (LongTimePattern)              u     2002-01-03 00:00:00Z                    yyyy'-'MM'-'dd HH':'mm':'ss'Z' (UniversalSortableDateTimePattern)              U     Thursday, January 03, 2002 8:00:00 AM              y     January, 2002                    MMMM, yyyy (YearMonthPattern)              Y     January, 2002                    MMMM, yyyy (YearMonthPattern)            */        }                #endregion 七.获得本周的周六和周日 ConvertDateToWeek #region ConvertDateToWeek        public static void ConvertDateToWeek(DateTime date,out DateTime firstdate,out DateTime lastdate)        {                DateTime first=System.DateTime.Now;            DateTime last=System.DateTime.Now;            switch (date.DayOfWeek)            {                                case System.DayOfWeek.Monday:                    first=date.AddDays(-1);                    last=date.AddDays(5);                    break;                case System.DayOfWeek.Tuesday:                    first=date.AddDays(-2);                    last=date.AddDays(4);                    break;                case System.DayOfWeek.Wednesday:                    first=date.AddDays(-3);                    last=date.AddDays(3);                    break;                case System.DayOfWeek.Thursday:                    first=date.AddDays(-4);                    last=date.AddDays(2);                    break;                case System.DayOfWeek.Friday:                    first=date.AddDays(-5);                    last=date.AddDays(1);                    break;                case System.DayOfWeek.Saturday:                    first=date.AddDays(-6);                    last=date;                    break;                case System.DayOfWeek.Sunday:                    first=date;                    last=date.AddDays(6);                    break;                            }            firstdate=first;            lastdate=last;        }        #endregion      // 调用 DateTime firstdate = System.DateTime.Now;    DateTime lastdate = System.DateTime.Now;ConvertDateToWeek(date, out  firstdate, out  lastdate);