VBA中当月的第一个星期一答案

【问题标题】：First Monday of Current Month in VBAVBA中当月的第一个星期一
【发布时间】：2017-08-08 09:44:51
【问题描述】：

使用 VBA 是否可以获得当月的第一个星期一？我原以为下面会起作用：-

DateSerial(Year(Date), Month(Date), ((7 - Weekday(DateSerial(Year(Date), Month(Date), 7))) + 2) Mod 7)

...但如果我今天使用它，我得到的日期是 2017 年 7 月 31 日，显然是上个月。

【问题讨论】：

你的标题真的很完美，为什么不google一下？
@Vityata 如果能找到答案，我不会在这里发帖...
没问题，我已经为你做了谷歌搜索:)

标签： vba ms-access

【解决方案1】：

编辑：这是一个可能的答案（so the first one in google is a false one）：

Public Function FirstMonday(myDate As Date) As Date

    Dim d As Date, w As Long
    d = DateSerial(Year(myDate), month(myDate), 1)
    w = Weekday(d, vbMonday)
    FirstMonday = d + IIf(w <> 1, 8 - w, 0)

End Function

这就是你的称呼：

Public Sub Test
   debug.print FirstMonday(Now)
End sub

总的来说，这是Excel Date Functions 的有趣读物。

【讨论】：

这个帖子没错，但最后一行需要是：FirstMonday = d + IIf(w = 1, 0, 8 - w)
@FloLie - 是的，vbSunday 没有收集任何信息。
@Vityata 谢谢

【解决方案2】：

你可以使用这个通用函数：

' Calculates the date of the occurrence of Weekday in the month of DateInMonth.
'
' If Occurrence is 0 or negative, the first occurrence of Weekday in the month is assumed.
' If Occurrence is 5 or larger, the last occurrence of Weekday in the month is assumed.
'
' If Weekday is invalid or not specified, the weekday of DateInMonth is used.
'
' 2016-06-09. Gustav Brock, Cactus Data ApS, CPH.
'
Public Function DateWeekdayInMonth( _
    ByVal DateInMonth As Date, _
    Optional ByVal Occurrence As Integer, _
    Optional ByVal Weekday As VbDayOfWeek = -1) _
    As Date

    Const DaysInWeek    As Integer = 7

    Dim Offset          As Integer
    Dim Month           As Integer
    Dim Year            As Integer
    Dim ResultDate      As Date

    ' Validate Weekday.
    Select Case Weekday
        Case _
            vbMonday, _
            vbTuesday, _
            vbWednesday, _
            vbThursday, _
            vbFriday, _
            vbSaturday, _
            vbSunday
        Case Else
            ' Zero, none or invalid value for VbDayOfWeek.
            Weekday = VBA.Weekday(DateInMonth)
    End Select

    ' Validate Occurence.
    If Occurrence <= 0 Then
        Occurrence = 1
    ElseIf Occurrence > 5 Then
        Occurrence = 5
    End If

    ' Start date.
    Month = VBA.Month(DateInMonth)
    Year = VBA.Year(DateInMonth)
    ResultDate = DateSerial(Year, Month, 1)

    ' Find offset of Weekday from first day of month.
    Offset = DaysInWeek * (Occurrence - 1) + (Weekday - VBA.Weekday(ResultDate) + DaysInWeek) Mod DaysInWeek
    ' Calculate result date.
    ResultDate = DateAdd("d", Offset, ResultDate)

    If Occurrence = 5 Then
        ' The latest occurrency of Weekday is requested.
        ' Check if there really is a fifth occurrence of Weekday in this month.
        If VBA.Month(ResultDate) <> Month Then
            ' There are only four occurrencies of Weekday in this month.
            ' Return the fourth as the latest.
            ResultDate = DateAdd("d", -DaysInWeek, ResultDate)
        End If
    End If

    DateWeekdayInMonth = ResultDate

End Function

然后：

FirstMonday = DateWeekdayInMonth(Date, 1, vbMonday)

【讨论】：

【解决方案3】：

运行以下宏，它会为您提供每月的第一个星期一：

Sub PromptFirstMondayofTheCurrentMonth()

Dim a As Variant

a = Date - Day(Date) + 1

MsgBox IIf(Weekday(a, vbMonday) = 1, 1, 9 - Weekday(a, vbMonday))

End Sub

【讨论】：