请问当月的第一天的表达式怎么写？

徐阿鹏

请问当月的第一天的表达式怎么写？vba？
最后一天怎么写？
谢谢！

skylark

To  徐阿鹏:
Function FirstOfMonth(InputDate As Date)
'  Return a date that is the first day of the month of the date passed
Dim D As Integer, M As Integer, Y As Integer

    If IsNull(InputDate) Then
        FirstOfMonth = Null
    Else
        D = Day(InputDate)
        M = Month(InputDate)
        Y = Year(InputDate)
        FirstOfMonth = DateSerial(Y, M, 1)
    End If
End Function

Function LastOfMonth(InputDate As Date)
'  Return a date that is the last day of the month of the date passed
Dim D As Integer, M As Integer, Y As Integer
   
    If IsNull(InputDate) Then
        LastOfMonth = Null
    Else
        D = Day(InputDate)
        M = Month(InputDate)
        Y = Year(InputDate)
        'find the first day of next month, then back up one day
        LastOfMonth = DateAdd("m", 1, DateSerial(Y, M, 1)) - 1
    End If
End Function
第一天   =firstofmonth(Now())
最后一天  =lastofmonth(Now())
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eio

Dim first, last As Date
first = Date - Format(Date, "dd") + 1
MsgBox "今日是“" & Date & "”。"
MsgBox "本月第一日是“" & first & "”。"
last = DateSerial(Year(Now), Month(Now) + 1, 1) - 1
MsgBox "本月最后一日是“" & last & "”。"

eio

再简化：
MsgBox DateSerial(Year(Now), Month(Now), 1)

MsgBox DateSerial(Year(Now), Month(Now) + 1, 1) - 1