Last day of the month in .NET

Question

Normally I use the below code, but is there a better way?

lastOfMonth = new DateTime(Now.Year, Now.Month, 1).AddMonths(1).AddDays(-1)

Answer 1

I use

DateTime now = DateTime.Today;
var lastDate = new DateTime(now.Year, now.Month, DateTime.DaysInMonth(now.Year, now.Month));

Answer 2

DateTime(year, month, DateTime.DaysInMonth(year, month)).

Answer 3

You can use CultureInfo.CurrentCulture.Calendar.GetDaysInMonth(Now.Year, Now.Month)

Answer 4

I would probably use DaysInMonth as it makes the code a bit more readable and easier to understand (although, I really like your trick :-)). This requieres a similar ammount of typing (which is quite a lot), so I would probably define an extension method:

DateTime LastDayOfMonth(this DateTime) {
  var days = DateTime.DaysInMonth(DateTime.Now.Year, DateTime.Now.Month);
  return new DateTime(DateTime.Now.Year, DateTime.Now.Month, days);
}

Now we can use DateTime.Now.LastDayOfMonth() which looks a lot better :-).

Answer 5

Try Noda time library. http://code.google.com/p/noda-time/