Finding the First and Last Day Of A Month in C#

If you've ever been tasked with finding records where they fall into a specific month, you can use the following method to calculate the first and last day of any month:

void GetMonthBoundaries(int month, int year, out DateTime firstDayOfMonth, out DateTime lastDayOfMonth) {    // how to get the 1st day of the month? it's always day 1, so this is simple enough    DateTime first = new DateTime(year, month, 1);    // how do we get the last day of the month when months have    // varying numbers of days?    //    // adding 1 month to "first" gives us the 1st day of the following month    // then if we subtract one second from that date, we get a DateTime that    // represents the last second of the last day of the desired month    // example: if month = 2 and year = 2011, then    // first = 2011-02-01 00:00:00    // last = 2011-02-28 23:59:59    DateTime last = first.AddMonths(1).AddSeconds(-1);    // if you're not concerned with time of day in your DateTime values    // and are only comparing days, then you can use the following line    // instead to get the last day:    //    // DateTime last = first.AddMonths(1).AddDays(-1);    // example: if month = 2 and year = 2011, then    // first = 2011-02-01 00:00:00    // last = 2011-02-28 00:00:00    firstDayOfMonth = first;    lastDayOfMonth = last; }