获得年天数、月天数

获得当前年的天数
int yeardays = System.Threading.Thread.CurrentThread.CurrentUICulture.Calendar.GetDaysInYear(DateTime.Now.Year);

获取当前年的周数

/// <summary>

/// 获得今年有几周

/// </summary>

/// <param name="year"></param>

/// <returns></returns>

public int GetWeekOfYear(int year)

{

DateTime the_Date = newDateTime(year,1,1);//本年的第一天

TimeSpantt=the_Date.AddYears(1)-the_Date;//求出本年有几天

return tt.Days / 7 + 1; //因为年只有366天和365天除以7有余数所以始终需要加一周

}

获取当前月的天数
第一种:
DateTime dtNow = DateTime.Now;

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

第二种:

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

第三种:

DateTimedtNow = DateTime.Today;

int days =dtNow .AddDays(1 - dtNow .Day).AddMonths(1).AddDays(-1).Day;