vb6 date parse

TextBox.ParseDate.vb

Private Sub ParseDate(ByRef tb As TextBox)
Rem 自訂函數

    On Error GoTo ErrHandle

    Dim a As Long
    Dim y, m, d As Integer
    Dim mod4 As Long
    
    y = Year(Now)
    m = Month(Now)
    d = Month(Now)
    
    a = CLng(Replace(Replace(tb.Text, "/", ""), "-", ""))
    Select Case a
    Case Is < 100 ' 日
    
        d = a

    Case Is < 10000 ' 月/日
    
        d = a Mod 100
        m = a / 100
    
    Case Is < 10000000 ' 年3/月/日
    
        mod4 = a Mod 10000
        d = mod4 Mod 100
        m = mod4 / 100
        y = a / 10000 + 2000
    
    Case Else ' 年/月/日
    
        mod4 = a Mod 10000
        d = mod4 Mod 100
        m = mod4 / 100
        y = a / 10000
    
    End Select
    
    tb.Text = Format(y, "0000") & "/" & Format(m, "00") & "/" & Format(d, "00")

PROC_EXIT:
    Exit Sub
    
ErrHandle:
    tb.Text = "" ' FAIL
    GoTo PROC_EXIT
End Sub

TextBox.ParseDate_eg.vb

Private Sub txtFields_Validate(Index As Integer, Cancel As Boolean)
Rem 自訂訊息處理

    Select Case Index
    Case 2, 6, 7, 8, 9 ' 日期欄位
        Debug.Print "txtFields_Validate 日期欄位"
        Debug.Print txtFields(Index).Text
        ParseDate txtFields(Index)
    End Select

End Sub