Private Sub txtProGr_KeyDown(ByVal sender As Object, ByVal e As _
  System.Windows.Forms.KeyEventArgs) Handles txtProGr.KeyDown
        Select Case e.KeyCode
            Case Keys.D0 To Keys.D9, Keys.A To Keys.F, Keys.NumPad0 To _
              Keys.NumPad9, Keys.Back
            Case Else
                e.SuppressKeyPress = True
        End Select
End Sub