Public MustInherit Class DataAccessClass
    Public Sub DoMagix()
        '** LOOK AT ME!!! **
        'Who am I? Why am I here? Where am I going?
        '** /LOOK AT ME!!! **
    End Sub
End Class

Public Class FooDAL
   Inherits DataAccessClass
End Class

Public Class WeeDAL
   Inherits DataAccessClass
End Class

Public MustInherit Class MinMax

    Protected Shared Property XString As String = ???

    Public Shared Function isValid(value As String) As Boolean
        Return min <= value <= max
    End Function

    Private Shared ReadOnly Property min As Double
        Get
            Return xd.SelectSingleNode(String.Format("FOEB/Restrictions/{0}", XString)).InnerText.Split("..")(0)
        End Get
    End Property
    Private Shared ReadOnly Property max As Double
        Get
            Return xd.SelectSingleNode(String.Format("FOEB/Restrictions/{0}", XString)).InnerText.Split("..")(1)
        End Get
    End Property
End Class

Public Class Restrictions
    Public Class A
        Inherits MinMax
    End Class
    Public Class B
        Inherits MinMax
    End Class

End Class


dim isOk as Boolean= Restrictions.A.isValid("10")

<?xml version="1.0" encoding="utf-8" ?>
<FOEB>
  <Restrictions>
    <A>1..21</A>
  </Restrictions>
</FOEB>