convert procedure Vb to xojo

General
1

This vb procedure allows only desired characters to be entered in Text Field.
special function need to be rewritten in xojo, as shown below,

Private Sub txtHdeg_KeyPress(KeyAscii As Integer)
    
    If [b]KeyAscii[/b] = 47 Then
    Select Case Len(TxtHdeg.text)
        Case 1, 2, 4, 5
        Case Else
        KeyAscii = 0
    End Select
    Else
    If InStr(1, "0123456789" & [b]Chr$(vbKeyBack) & Chr$(vbKeySpace), Chr$(KeyAscii)[/b]) = 0 Then
      KeyAscii = 0
    End If
End Sub
2

Please check keydown event.
You may want to make a select case on asc(key) to return true for those you want to disallow.

3 
FUNCTION KeyDown(key as string) as Boolean
 If AscB(key)=47 then 
    Select Case Len(TxtHdeg.text)
        Case 1, 2, 4, 5
            return false
        Case Else
            return true
    End Select
    Else
    If InStr(1, "0123456789" + ChrB(8) + ChrB(32), key) = 0 Then
     return false
    End If
    return true
End Function
4

[code] If AscB(key)=47 then

Select Case Len(TFhauteurdeg.text)
Case 1, 2, 4, 5
  return false
Case Else
  return true
End Select

Else
If InStr(1, “0123456789” + ChrB(8) + ChrB(32), key) = 0 Then
return true
End If
End If
return False[/code]

Under KeyDown event running properly, many thanks.