使用以下扩展方法:
public static class DateTimeExtensions
{
///<summary>Gets the first week day following a date.</summary>
///<param name="date">The date.</param>
///<param name="dayOfWeek">The day of week to return.</param>
///<returns>The first dayOfWeek day following date, or date if it is on dayOfWeek.</returns>
public static DateTime Next(this DateTime date, DayOfWeek dayOfWeek) {
return date.AddDays((dayOfWeek < date.DayOfWeek ? 7 : 0) + dayOfWeek - date.DayOfWeek);
}
}
然后你可以写
new DateTime(2010, 07, 01).Next(DayOfWeek.Monday).AddDays((2 - 1) * 7);
或者,作为一个函数:
public DateTime GetNthWeekofMonth(DateTime date, int nthWeek, DayOfWeek dayOfWeek) {
return date.Next(dayOfWeek).AddDays((nthWeek - 1) * 7);
}
(我需要减去一个,因为date.Next(dayOfWeek)
那一天已经是第一次出现)