C#-日期時間-時間日期操作

c# 獲取當前月份最大天數

DateTime dtNow = DateTime.Now;
int daycount = DateTime.DaysInMonth(dtNow.Year, dtNow.Month);

int days = System.Threading.Thread.CurrentThread.CurrentUICulture.Calendar.GetDaysInMonth(DateTime.Now.Year, DateTime.Now.Month);

c#獲取某月的第一天

private DateTime FirstDayOfMonth(DateTime datetime)
{
     return datetime.AddDays(1 - datetime.Day);
}

c#獲取某月的最後一天

private DateTime LastDayOfMonth(DateTime datetime)
{
    return datetime.AddDays(1 - datetime.Day).AddMonths(1).AddDays(-1);
}

C# 如何根據當前地日期，獲取兩個月前地日期

DateTime.Now.AddMonths(-2).ToString()