'下2个月的第一天并减去一天就为下月的最后一天

Function LastdayOfnextMonth(inputdate As Date)
Dim D As Integer, m As Integer, Y As Integer
    If IsNull(inputdate) Then
        LastdayOfnextMonth = Null
    Else
        D = day(inputdate)
        m = Month(inputdate)
        Y = Year(inputdate)
        '下2个月的第一天并减去一天就为下月的最后一天
        LastdayOfnextMonth = DateAdd("m", 2, DateSerial(Y, m, 1)) - 1
    End If
End Function