【Excel VBA】检查日期输入校验函数

    Sub 检查日期录入()
      Dim strDate As String
      strDate = "20210431"
      
      Dim bolCheck As Boolean
      bolCheck = CheckDate(strDate)
    End Sub
    
    Function CheckDate(DateString As String) As Boolean
      CheckDate = False '首先为函数设定False的结果，具体返回结果会根据后续的执行情况而定
      If Len(DateString) <> 8 Then
    '如果传入参数的长度不是8，则返回False
    CheckDate = False
    Exit Function
      End If
    
      Dim yyyy As Integer
    yyyy = Val(Left(DateString, 4)) '获取年份
      Dim mm As Integer
    mm = Val(Mid(DateString, 5, 2)) '获取月份
      Dim dd As Integer
    dd = Val(Right(DateString, 2)) '获取日
      If mm > 0 And mm < 13 Then
    If dd > 0 Then
      Select Case mm
        Case 2
          If (yyyy Mod 4) <> 0 Or (yyyy Mod 100) = 0 And (yyyy Mod 400) <> 0 Then
            '如果不是闰年的情形
            If dd < 29 Then
              CheckDate = True
              Exit Function
            Else
              CheckDate = False
              Exit Function
            End If
          End If
          '如果是闰年
          If dd < 30 Then
            CheckDate = True
            Exit Function
          Else
            CheckDate = False
            Exit Function
          End If
        Case 4, 6, 9, 11
          If dd < 31 Then
            CheckDate = True
            Exit Function
          Else
            CheckDate = False
            Exit Function
          End If
        Case Else
          If dd < 32 Then
            CheckDate = True
            Exit Function
          Else
            CheckDate = False
            Exit Function
          End If
      End Select
    End If
      End If
    End Function