计算下个月的最后一天

Question

我试图在C＃中使用DateTime函数来计算下个月的最后一天。

例如，今天是2015年12月17日。我希望DateTime函数返回2016年1月31日（下个月的最后一天）。

我使用以下来计算下个月的第一天（这是有效的）：

DateTime firstDayNextMonth = DateTime.Today.AddDays(-DateTime.Now.Day+1).AddMonths(1);

Answer 1

DateTime reference = DateTime.Now;
DateTime firstDayThisMonth = new DateTime(reference.Year, reference.Month, 1);
DateTime firstDayPlusTwoMonths = firstDayThisMonth.AddMonths(2);
DateTime lastDayNextMonth = firstDayPlusTwoMonths.AddDays(-1);
DateTime endOfLastDayNextMonth = firstDayPlusTwoMonths.AddTicks(-1);

演示： http ： //rextester.com/AKDI52378

Answer 2

//system date or any date u want this case it is a calendar picker - 22/03/2016
DateTime today = dtpFrom.Value;

//Add a month to your date example , it now becomes - 22/04/2016
DateTime endOfMonth = new DateTime(today.Year, today.Month,today.Day).AddMonths(1);

//Get the last date off the above which is - 30
int getlastday = DateTime.DaysInMonth(endOfMonth.Year, endOfMonth.Month);

//Now set the date to the value  which will be the last day off the next month - 30/04/2016
DateTime newDate = new DateTime(endOfMonth.Year, endOfMonth.Month, getlastday);

Answer 3

尝试这个：

int Day= DateTime.DaysInMonth(DateTime.Now.Year, DateTime.Now.Month+1>12 ? 01 : DateTime.Now.Month+1 );

Answer 4

 var lastDayInNextMonth = DateTime.DaysInMonth(DateTime.Now.AddMonths(1).Year, DateTime.Now.AddMonths(1).Month );  

@ Ben： DateTime.Now.AddMonths(1)将在当前日期增加1个月而不减去11个月。

DateTime.Now.AddMonths(1).Year将给2016而不是2015参考附图

Answer 5

DateTime.DaysInMonth(DateTime.Now.AddMonths(1).Year, DateTime.Now.AddMonths(1).Month);