Question

我正在解决一个问题，问题是你应该从2000年到2011年获得black fridays的所有列表。那么如何在vb.net中做到这一点？有什么帮助吗？

Answer 1

刚刚写了这段代码。在所有条件下测试。希望能帮助到你。祝你好运：）

    Dim BlackFridayList As String = ""
    Dim dt As Date
    Dim weeknumber As Integer = 1


    For i = 2000 To 2011
        dt = New Date(i, 11, 1)
        weeknumber = 1
        ' find first friday
        While dt.DayOfWeek <> DayOfWeek.Friday
            dt = dt.AddDays(1)
            weeknumber = weeknumber + 1
        End While


        If weeknumber = 1 And (dt.Day + 28 < Date.DaysInMonth(dt.Year, dt.Month)) Then
            ' add four weeks
            dt = dt.AddDays(28)
        Else
            ' add three weeks
            dt = dt.AddDays(21)
        End If

        BlackFridayList = BlackFridayList & dt.ToLongDateString & vbCrLf
    Next

    MsgBox(BlackFridayList) 'List of all black fridays

Answer 2

黑色星期五是11月第四个星期四之后的第二天。您可以使用DateTime函数确定这些年份的日期。

http://msdn.microsoft.com/en-us/library/system.datetime%28v=vs.110%29.aspx

Answer 3

Function BlackFriday(Year as Integer) As DateTime
    Dim november1 = New DateTime(Year, 11, 1)
    Dim firstThursday = Enumerable.Range(0, 7).Select(Function(x) november1.AddDays(x)).First(Function(x) x.DayOfWeek = DayOfWeek.Thursday)
    Return firstThursday.AddDays(22)
End Function

使用它：

Dim blackFridays = Enumerable.Range(2000,12).Select(Function(year) BlackFriday(year)).ToList

如何在vb.net中获得所有黑色星期五？

3 个答案: