c# - 如何获取下个月的 4. 星期三作为 DateTime？

Question

我需要一个函数来给出下个月的第 n 个 DateTime。例如:我需要下个月的第 4 个星期三。

我的代码提供了错误的日期:

private static DateTime FindNextDay(DayOfWeek dayOfWeek, DateTime fday, Int32 instance)
{
    DateTime day = new DateTime(fday.Year, fday.Month, 1, fday.Hour, fday.Minute, fday.Second);
    // DateTime day is in this Example= 2014-08.01 11.00 AM   
     if (instance == 2)
     {
         day = day.AddDays(7);
     }
     else if (instance == 3)
     {
         day = day.AddDays(14);
     }
     else if (instance == 4)  //if the 4th week is requested
     {
         day = day.AddDays(28); // i add 28 days
     }
     while (day.DayOfWeek != dayOfWeek)
     {
         day = day.AddDays(1);   // and search the wednesday and return it back
     }
    return day;
}

你能告诉我一个更好的解决方案吗？

Answer 1

像这样的..

获取下个月的第一天，记录您遇到的 星期三 的数量，当您找到一个时将其添加到其中。计数为 4 时返回。

private static DateTime GetFourthWednesday()
{
    DateTime firstOfMonth = new DateTime(DateTime.Now.AddMonths(1).Year, DateTime.Now.AddMonths(1).Month, 1);

    int count = 0;
    while (count < 4)
    {
        if (firstOfMonth.DayOfWeek == DayOfWeek.Wednesday)
        {
            count++;
        }

        if (count == 4)
        {
            return firstOfMonth;
        }

        firstOfMonth = firstOfMonth.AddDays(1);

    }

    return firstOfMonth;
}

如果今天运行，给出 27/08/2014