TextBox Datumsformat

Private Sub TextBox1_KeyPress(ByVal KeyAscii As MSForms.ReturnInteger)
Const cDatum As String = "01.01.2000" '2000=Schaltjahr
Dim ka As Byte, dat As String
ka = KeyAscii
Select Case ka
Case 48 To 57, 46
Case Else: ka = 0
End Select
With Me.TextBox1
dat = .Text & Chr(ka) & Mid(cDatum, Len(.Text & Chr(ka)) + 1)
If Not IsDate(dat) Then ka = 0
If Val(Split(dat, ".")(1)) > 12 Then ka = 0
If Len(.Text & Chr(ka)) > 10 Then ka = 0
End With
KeyAscii = ka
End Sub