VB.NET - 给定一个日期,我怎样才能获得下周五的日期？

Question

给定Date,如何在.NET Framework 2.0中的VB.NET中获取星期五(或任何其他工作日)的日期？

Answer 1

Dim NextFriday as Date= GetNext(DayOfWeek.Friday) 

Function GetNext(ByVal d As DayOfWeek, Optional ByVal StartDate As Date = Nothing) As Date
    If StartDate = DateTime.MinValue Then StartDate = Now
    For p As Integer = 1 To 7
        If StartDate.AddDays(p).DayOfWeek = d Then Return StartDate.AddDays(p)
    Next
End Function

编辑:更新答案以允许startdate(可选).

下周五:

Dim NextFriday As Date = GetNext(DayOfWeek.Friday)

从现在起15天后的下周五是什么时候:

Dim AnotherFriday As Date = GetNext(DayOfWeek.Friday,now.addays(15))

Answer 2

'
Public Function nextDOW(whDayOfWeek As DayOfWeek, _
                        Optional theDate As DateTime = Nothing) As DateTime
    'returns the next day of the week
    If theDate = Nothing Then theDate = DateTime.Now
    Dim d As DateTime = theDate.AddDays(whDayOfWeek - theDate.DayOfWeek)
    Return If(d <= theDate, d.AddDays(7), d)
End Function

Answer 3

Dim someDate As DateTime = ... 'input date
Dim nextFriday As DateTime = someDate
While nextFriday.DayOfWeek <> DayOfWeek.Friday
    nextFriday = nextFriday.AddDays(1)
End While

Console.WriteLine(nextFriday)