C# Round Datetime Extension To Nearest Minute And Smaller Units Are Rounded To Zero

C# DateTime extensions that rounds a datetime Up, Down or Nearest minutes and smaller units are rounded to zero.

As used in my Solo SCRUM Sprinter App - book work effort in Outlook calendar directly

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using System; public static class Program { /// <summary> /// Rounds datetime up, down or to nearest minutes and all smaller units to zero /// </summary> /// <param name="dt">ignore, implicitly passed</param> /// <param name="rndmin">mins to round to</param> /// <param name="directn">Up,Down,Nearest</param> /// <returns>rounded datetime with all smaller units than mins rounded off</returns> public static DateTime RoundToNearestMinuteProper(this DateTime dt, int rndmin, RoundingDirection directn) { if (rndmin == 0) //can be > 60 mins return dt; TimeSpan d = TimeSpan.FromMinutes(rndmin); //this can be passed as a parameter, or use any timespan unit FromDays, FromHours, etc. long delta = 0; Int64 modTicks = dt.Ticks % d.Ticks; switch (directn) { case RoundingDirection.Up: delta = (modTicks != 0) ? d.Ticks - modTicks : 0; break; case RoundingDirection.Down: delta = -modTicks; break; case RoundingDirection.Nearest: { bool roundUp = modTicks > (d.Ticks / 2); var offset = roundUp ? d.Ticks : 0; delta = offset - modTicks; break; } } return new DateTime(dt.Ticks + delta, dt.Kind); } public enum RoundingDirection { Up, Down, Nearest } public static void Main() { //var dt = new DateTime(2001, 1, 1, 0, 0, 0, 000); //var dt = new DateTime(2018, 08, 03, 10, 7, 30, 000); //8/3/2018 10:00:00 AM Nearest, re 15/2 = 7.5 mins or 7 mins and 30 secs var dt = new DateTime(2018, 08, 03, 10, 7, 31, 000); //8/3/2018 10:15:00 AM Nearest Console.WriteLine(dt.RoundToNearestMinuteProper(15, RoundingDirection.Up)); Console.WriteLine(dt.RoundToNearestMinuteProper(15, RoundingDirection.Down)); Console.WriteLine(dt.RoundToNearestMinuteProper(15, RoundingDirection.Nearest)); } }