private void inputParam1_TextChanged(object sender, TextChangedEventArgs e) { if (inputParam1.Text != "[ASK]" && inputParam2.Text != "[ASK]") { BadInputLab.Visibility = System.Windows.Visibility.Hidden; OKButt.IsEnabled = true; } else { BadInputLab.Visibility = System.Windows.Visibility.Visible; OKButt.IsEnabled = false; } }