我怎样才能把时间四舍五入到最近的 X 分钟?

DateTime RoundUp(DateTime dt, TimeSpan d)
{
return new DateTime((dt.Ticks + d.Ticks - 1) / d.Ticks * d.Ticks, dt.Kind);
}

例子:

var dt1 = RoundUp(DateTime.Parse("2011-08-11 16:59"), TimeSpan.FromMinutes(15));
// dt1 == {11/08/2011 17:00:00}


var dt2 = RoundUp(DateTime.Parse("2011-08-11 17:00"), TimeSpan.FromMinutes(15));
// dt2 == {11/08/2011 17:00:00}


var dt3 = RoundUp(DateTime.Parse("2011-08-11 17:01"), TimeSpan.FromMinutes(15));
// dt3 == {11/08/2011 17:15:00}

优雅?

dt.AddSeconds(900 - (x.Minute * 60 + x.Second) % 900)

void Main()
{
var date1 = new DateTime(2011, 8, 11, 16, 59, 00);
date1.Round15().Dump();


var date2 = new DateTime(2011, 8, 11, 17, 00, 02);
date2.Round15().Dump();


var date3 = new DateTime(2011, 8, 11, 17, 01, 23);
date3.Round15().Dump();


var date4 = new DateTime(2011, 8, 11, 17, 00, 00);
date4.Round15().Dump();
}


public static class Extentions
{
public static DateTime Round15(this DateTime value)
{
var ticksIn15Mins = TimeSpan.FromMinutes(15).Ticks;


return (value.Ticks % ticksIn15Mins == 0) ? value : new DateTime((value.Ticks / ticksIn15Mins + 1) * ticksIn15Mins);
}
}

结果:

8/11/2011 5:00:00 PM
8/11/2011 5:15:00 PM
8/11/2011 5:15:00 PM
8/11/2011 5:00:00 PM

由于我讨厌重新发明轮子，我可能会遵循这个算法将DateTime值舍入到指定的时间增量(Timespan):

• 将DateTime值转换为表示TimeSpan单位的整数和小数的十进制浮点值。
• 使用Math.Round()将其舍入为整数。
• 通过将四舍五入的整数乘以TimeSpan单位中的刻度数来缩小到刻度。
• 从整数中实例化一个新的DateTime值，并将其返回给调用者。

代码如下:

public static class DateTimeExtensions
{


public static DateTime Round( this DateTime value , TimeSpan unit )
{
return Round( value , unit , default(MidpointRounding) ) ;
}


public static DateTime Round( this DateTime value , TimeSpan unit , MidpointRounding style )
{
if ( unit <= TimeSpan.Zero ) throw new ArgumentOutOfRangeException("unit" , "value must be positive") ;


Decimal  units        = (decimal) value.Ticks / (decimal) unit.Ticks ;
Decimal  roundedUnits = Math.Round( units , style ) ;
long     roundedTicks = (long) roundedUnits * unit.Ticks ;
DateTime instance     = new DateTime( roundedTicks ) ;


return instance ;
}


}

如果你需要舍入到最近的时间间隔(不是up) 那么我建议使用下面的

    static DateTime RoundToNearestInterval(DateTime dt, TimeSpan d)
{
int f=0;
double m = (double)(dt.Ticks % d.Ticks) / d.Ticks;
if (m >= 0.5)
f=1;
return new DateTime(((dt.Ticks/ d.Ticks)+f) * d.Ticks);
}

注意:以上公式不正确，即:

DateTime RoundUp(DateTime dt, TimeSpan d)
{
return new DateTime(((dt.Ticks + d.Ticks - 1) / d.Ticks) * d.Ticks);
}

应重写为:

DateTime RoundUp(DateTime dt, TimeSpan d)
{
return new DateTime(((dt.Ticks + d.Ticks/2) / d.Ticks) * d.Ticks);
}

提出了一个不涉及乘和分 long数字的解决方案。

public static DateTime RoundUp(this DateTime dt, TimeSpan d)
{
var modTicks = dt.Ticks % d.Ticks;
var delta = modTicks != 0 ? d.Ticks - modTicks : 0;
return new DateTime(dt.Ticks + delta, dt.Kind);
}


public static DateTime RoundDown(this DateTime dt, TimeSpan d)
{
var delta = dt.Ticks % d.Ticks;
return new DateTime(dt.Ticks - delta, dt.Kind);
}


public static DateTime RoundToNearest(this DateTime dt, TimeSpan d)
{
var delta = dt.Ticks % d.Ticks;
bool roundUp = delta > d.Ticks / 2;
var offset = roundUp ? d.Ticks : 0;


return new DateTime(dt.Ticks + offset - delta, dt.Kind);
}

用法:

var date = new DateTime(2010, 02, 05, 10, 35, 25, 450); // 2010/02/05 10:35:25
var roundedUp = date.RoundUp(TimeSpan.FromMinutes(15)); // 2010/02/05 10:45:00
var roundedDown = date.RoundDown(TimeSpan.FromMinutes(15)); // 2010/02/05 10:30:00
var roundedToNearest = date.RoundToNearest(TimeSpan.FromMinutes(15)); // 2010/02/05 10:30:00

一个更详细的解决方案，它使用模，避免不必要的计算。

public static class DateTimeExtensions
{
public static DateTime RoundUp(this DateTime dt, TimeSpan ts)
{
return Round(dt, ts, true);
}


public static DateTime RoundDown(this DateTime dt, TimeSpan ts)
{
return Round(dt, ts, false);
}


private static DateTime Round(DateTime dt, TimeSpan ts, bool up)
{
var remainder = dt.Ticks % ts.Ticks;
if (remainder == 0)
{
return dt;
}


long delta;
if (up)
{
delta = ts.Ticks - remainder;
}
else
{
delta = -remainder;
}


return dt.AddTicks(delta);
}
}

这是一个简单的方法，可以四舍五入到最接近的1分钟。它保留了DateTime的TimeZone和Kind信息。可以根据自己的需要进行修改(如果需要四舍五入到最近的5分钟，等等)。

DateTime dbNowExact = DateTime.Now;
DateTime dbNowRound1 = (dbNowExact.Millisecond == 0 ? dbNowExact : dbNowExact.AddMilliseconds(1000 - dbNowExact.Millisecond));
DateTime dbNowRound2 = (dbNowRound1.Second == 0 ? dbNowRound1 : dbNowRound1.AddSeconds(60 - dbNowRound1.Second));
DateTime dbNow = dbNowRound2;

您可以使用此方法，它使用指定的日期来确保它维护之前在datetime对象中指定的任何全球化和datetime类型。

const long LNG_OneMinuteInTicks = 600000000;
/// <summary>
/// Round the datetime to the nearest minute
/// </summary>
/// <param name = "dateTime"></param>
/// <param name = "numberMinutes">The number minute use to round the time to</param>
/// <returns></returns>
public static DateTime Round(DateTime dateTime, int numberMinutes = 1)
{
long roundedMinutesInTicks = LNG_OneMinuteInTicks * numberMinutes;
long remainderTicks = dateTime.Ticks % roundedMinutesInTicks;
if (remainderTicks < roundedMinutesInTicks / 2)
{
// round down
return dateTime.AddTicks(-remainderTicks);
}


// round up
return dateTime.AddTicks(roundedMinutesInTicks - remainderTicks);
}

。Net Fiddle Test

如果你想使用TimeSpan来四舍五入，你可以使用这个。

/// <summary>
/// Round the datetime
/// </summary>
/// <example>Round(dt, TimeSpan.FromMinutes(5)); => round the time to the nearest 5 minutes.</example>
/// <param name = "dateTime"></param>
/// <param name = "roundBy">The time use to round the time to</param>
/// <returns></returns>
public static DateTime Round(DateTime dateTime, TimeSpan roundBy)
{
long remainderTicks = dateTime.Ticks % roundBy.Ticks;
if (remainderTicks < roundBy.Ticks / 2)
{
// round down
return dateTime.AddTicks(-remainderTicks);
}


// round up
return dateTime.AddTicks(roundBy.Ticks - remainderTicks);
}

TimeSpan Fiddle

我的版本

DateTime newDateTimeObject = oldDateTimeObject.AddMinutes(15 - oldDateTimeObject.Minute % 15);

作为一种方法，它会像这样锁定

public static DateTime GetNextQuarterHour(DateTime oldDateTimeObject)
{
return oldDateTimeObject.AddMinutes(15 - oldDateTimeObject.Minute % 15);
}

是这样称呼的

DateTime thisIsNow = DateTime.Now;
DateTime nextQuarterHour = GetNextQuarterHour(thisIsNow);

雷蒙史密特带DateTime的解决方案。MaxValue检查:

DateTime RoundUp(DateTime dt, TimeSpan d) =>
dt switch
{
var max when max.Equals(DateTime.MaxValue) => max,
var v => new DateTime((v.Ticks + d.Ticks - 1) / d.Ticks * d.Ticks, v.Kind)
};

我的DateTimeOffset版本，基于Ramon的回答:

public static class DateExtensions
{
public static DateTimeOffset RoundUp(this DateTimeOffset dt, TimeSpan d)
{
return new DateTimeOffset((dt.Ticks + d.Ticks - 1) / d.Ticks * d.Ticks, dt.Offset);
}
}

你可以试试这个:

string[] parts = ((DateTime)date_time.ToString("HH:mm:ss").Split(':');
int hr = Convert.ToInt32(parts[0]);
int mn = Convert.ToInt32(parts[1]);
int sec2min = (int)Math.Round(Convert.ToDouble(parts[2]) / 60.0, 0);


string adjTime = string.Format("1900-01-01 {0:00}:{1:00}:00.000",
(mn + sec2min > 59 ? (hr + 1 > 23 ? 0 : hr + 1) : hr),
mn + sec2min > 59 ? 60 - mn + sec2min : mn + sec2min);

每个部分(hr, min)必须增加并调整到适当的溢出值，如59分钟>00, hr加上1，如果是23,hr就变成00。 例07:34:57四舍五入到07:35,09:59:45四舍五入到10:00,23:59:45四舍五入到00:00，这是第二天的时间

public static class DateTimeExtensions
{
public static DateTime RoundToTicks(this DateTime target, long ticks) => new DateTime((target.Ticks + ticks / 2) / ticks * ticks, target.Kind);
public static DateTime RoundUpToTicks(this DateTime target, long ticks) => new DateTime((target.Ticks + ticks - 1) / ticks * ticks, target.Kind);
public static DateTime RoundDownToTicks(this DateTime target, long ticks) => new DateTime(target.Ticks / ticks * ticks, target.Kind);


public static DateTime Round(this DateTime target, TimeSpan round) => RoundToTicks(target, round.Ticks);
public static DateTime RoundUp(this DateTime target, TimeSpan round) => RoundUpToTicks(target, round.Ticks);
public static DateTime RoundDown(this DateTime target, TimeSpan round) => RoundDownToTicks(target, round.Ticks);


public static DateTime RoundToMinutes(this DateTime target, int minutes = 1) => RoundToTicks(target, minutes * TimeSpan.TicksPerMinute);
public static DateTime RoundUpToMinutes(this DateTime target, int minutes = 1) => RoundUpToTicks(target, minutes * TimeSpan.TicksPerMinute);
public static DateTime RoundDownToMinutes(this DateTime target, int minutes = 1) => RoundDownToTicks(target, minutes * TimeSpan.TicksPerMinute);


public static DateTime RoundToHours(this DateTime target, int hours = 1) => RoundToTicks(target, hours * TimeSpan.TicksPerHour);
public static DateTime RoundUpToHours(this DateTime target, int hours = 1) => RoundUpToTicks(target, hours * TimeSpan.TicksPerHour);
public static DateTime RoundDownToHours(this DateTime target, int hours = 1) => RoundDownToTicks(target, hours * TimeSpan.TicksPerHour);


public static DateTime RoundToDays(this DateTime target, int days = 1) => RoundToTicks(target, days * TimeSpan.TicksPerDay);
public static DateTime RoundUpToDays(this DateTime target, int days = 1) => RoundUpToTicks(target, days * TimeSpan.TicksPerDay);
public static DateTime RoundDownToDays(this DateTime target, int days = 1) => RoundDownToTicks(target, days * TimeSpan.TicksPerDay);
}