VB.NET - 给定一个日期，我如何得到下面的星期五的日期？

Question

给定一个日期，如何在.NET Framework 2.0中的VB.NET中获得下一个星期五（或任何其他工作日）的日期？

Answer 1

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) 

Answer 2

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：更新的答案，让一个开始日期（可选）。

获得下周五：

Dim NextFriday As Date = GetNext(DayOfWeek.Friday) 

什么是下周五后15天从现在开始：

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

Answer 3

' 
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 4

又一个变化与以上那些，只是没有循环：

Private Function GetFridayDate(StartingDate As Date, DayToGet As DayOfWeek, iDays As Integer) As Date 
     Return StartingDate.AddDays(iDays + (DayToGet - StartingDate.DayOfWeek)) 
End Function 

如何使用函数的示例n

Dim dtStartDate As Date 

dtStartDate = GetFridayDate(Now, DayOfWeek.Friday, -7) ' Last Week Friday 

dtStartDate = GetFridayDate(Now, DayOfWeek.Friday, 0) ' This Week Friday 

dtStartDate = GetFridayDate(Now, DayOfWeek.Friday, 7) ' Next Week Friday 

dtStartDate = GetFridayDate(Now, DayOfWeek.Friday, 14) ' Week after Next Friday