C＃.Net从当前日期开始上个月的最后一天

Question

快速表达任何人都可以吗？

Answer 1

var now = DateTime.Now;    
var firstDayCurrentMonth = new DateTime(now.Year, now.Month, 1);

var lastDayLastMonth = firstDayCurrentMonth.AddDays(-1);

Answer 2

DateTime now = DateTime.Now;
DateTime lastDayOfLastMonth = now.Date.AddDays(-now.Day);

Answer 3

尝试DateTime.DaysInMonth（int year，int month）方法

这是一个例子：

DateTime oneMonthAgo = DateTime.Now.AddMonths(-1);
int days = DateTime.DaysInMonth(oneMonthAgo.Year, oneMonthAgo.Month);