Protected Overrides Sub OnKeypress(ByVal e As System.Windows.Forms.KeyPressEventArgs)
        '---protected modifier allows sub to be used in classes derived from this one and be used in
        '   the assembly of this project but not other assemblies

        Select Case m_LegalKeys
            Case KeystrokeOption.All           'allow any keystroke
                e.Handled = False                'don't block 
            Case KeystrokeOption.LettersOnly   'lower or upper case letters & backspace key

                If UCase(e.KeyChar) >= "A" And UCase(e.KeyChar) <= "Z" _
                    Or e.KeyChar = ControlChars.Back _
                    Or ConsoleKey.Spacebar Then       'space 
                    e.Handled = False
                Else
                    e.Handled = True      'block it
                End If
            Case KeystrokeOption.NumbersOnly 'numbers only & "." & Backspace key
                If (e.KeyChar >= "0" And e.KeyChar <= "9") _
                    Or e.KeyChar = "." _
                    Or e.KeyChar = ControlChars.Back Then
                    e.Handled = False
                Else
                    e.Handled = True      'block it
                End If
            Case Else
                e.Handled = True
        End Select

    End Sub