Question

I need to test that a DateTime is at the beginning of a some unit of time for various units. This is the code I’m using right now:

/// ignoring milliseconds all the way down  bool IsMinute(DateTime dt) {   return dt.Second == 0; }  bool IsHour(DateTime dt)  {   return dt.Second == 0 && dt.Minute == 0; }    bool IsDay(DateTime dt)  {   return dt.Date == dt; }  bool IsMonth(DateTime dt)  {   return dt.Date == dt && dt.Day == 1; }  bool IsYear(DateTime dt)  {   return dt.Date == dt && dt.DayOfYear == 1; } 

Any ideas for improvements?

Answer 1

(EDIT: IsMonth is fine because it first checks that it’s just a date.)

You might want to chain these together – for example, your IsMinute should probably check for milliseconds. Rather than add that test to IsHour as well, just make IsHour check for IsMinute first. Chaining is simple:

bool IsHour(DateTime dt)  {     return IsMinute(dt) && dt.Minute == 0; } 

Another alternative might be to make them extension methods:

public static bool IsHour(this DateTime dt)  {     return dt.IsMinute() && dt.Minute == 0; } 

I’d definitely make them static either way 🙂