Question

想要了解这些年中每个月的周一，周三和周六的日期。我试图以这种方式管理它;

DateTime today = DateTime.UtcNow;
int deltaMonday = DayOfWeek.Monday - today.DayOfWeek;
var monday = today.AddDays(deltaMonday);


int deltaWednesday = DayOfWeek.Wednesday - today.DayOfWeek;
var wednesday = today.AddDays(deltaWednesday);

int deltaSaturday = DayOfWeek.Saturday - today.DayOfWeek;
var saturday = today.AddDays(deltaSaturday);

但我希望显示下一个（例如）星期一的日期，如果这个（星期）的星期一去世，同样的星期三和星期六也是如此。如果（当前）月份过去，则应显示下个月的日期。有没有更短的方法来获取或更改我的代码？

Answer 1

试试这个 -

 DateTime today = DateTime.UtcNow;
 int deltaMonday = DayOfWeek.Monday - today.DayOfWeek;
 var monday = today.AddDays(deltaMonday += deltaMonday < 0 ? 7 : 0);

 int deltaWednesday = DayOfWeek.Wednesday - today.DayOfWeek;
 var wednesday = today.AddDays(deltaWednesday += deltaWednesday < 0 ? 7 : 0);

 int deltaSaturday = DayOfWeek.Saturday - today.DayOfWeek;
 var saturday = today.AddDays(deltaSaturday += deltaSaturday < 0 ? 7 : 0);

简而言之，如果这一天过去了，那就是差异是负面的，那么只需要加7天。

如果需要检查几个月，请做类似的事情。

Answer 2

试试这个 -

 Public DateTime GetNextWeekday(DayOfWeek day)
 {
     DateTime result = DateTime.Now.AddDays(1);
     while( result.DayOfWeek != day )
          result = result.AddDays(1);
     return result;
 }

 DateTime deltaMonday=GetNextWeekday(1)
 DateTime deltaWednesday=GetNextWeekday(3)
 DateTime deltaSaturday=GetNextWeekday(6)

Answer 3

如果你知道需要多少天才能看，你可以使用linq。下面的代码在接下来的100天内查找所有星期一，星期三和星期六：

var daysAhead = Enumerable.Range(0, 100);
var dates = daysAhead.Select (a => DateTime.Today.AddDays(a))
                         .Where (a => a.DayOfWeek == DayOfWeek.Monday ||
                                      a.DayOfWeek == DayOfWeek.Wednesday ||
                                      a.DayOfWeek == DayOfWeek.Saturday ).ToList();

如何获取每个月和每年特定日期的日期？

3 个答案: