如何在c#4.0中获取给定年份(int),给定月份(int)和给定周(int){示例年份：2011月份：07周：04}的开始和结束日期？提前致谢.
2011年07月的开始日期和月份的周数是04.
解决方法
Google是你的朋友.
月：
public DateTime FirstDayOfMonthFromDateTime(DateTime dateTime)
{
return new DateTime(dateTime.Year,dateTime.Month,1);
}
public DateTime LastDayOfMonthFromDateTime(DateTime dateTime)
{
DateTime firstDayOfTheMonth = new DateTime(dateTime.Year,1);
return firstDayOfTheMonth.AddMonths(1).AddDays(-1);
}
您可以多年来做类似的事情：
DateTime time = new DateTime(2011,1,1); time.AddYears(1).AddDays(-1);
week需要使用CultureInfo.FirstDay(或者你想要设置为一周的第一天,在某些国家是星期一,有时是星期天).
/// <summary>
/// Returns the first day of the week that the specified
/// date is in using the current culture.
/// </summary>
public static DateTime GetFirstDayOfWeek(DateTime dayInWeek)
{
CultureInfo defaultCultureInfo = CultureInfo.CurrentCulture;
return GetFirstDateOfWeek(dayInWeek,defaultCultureInfo);
}
/// <summary>
/// Returns the first day of the week that the specified date
/// is in.
/// </summary>
public static DateTime GetFirstDayOfWeek(DateTime dayInWeek,CultureInfo cultureInfo)
{
DayOfWeek firstDay = cultureInfo.DateTimeFormat.FirstDayOfWeek;
DateTime firstDayInWeek = dayInWeek.Date;
while (firstDayInWeek.DayOfWeek != firstDay)
firstDayInWeek = firstDayInWeek.AddDays(-1);
return firstDayInWeek;
}
