private async void ModifyButton_Click(object sender, RoutedEventArgs e)
 {
     var dialog = new AddOrModifyDevice((Device)DevicesListView.SelectedItem);
     await DialogHost.Show(dialog, "DeviceDialog");
 }
 private async void AddButton_Click(object sender, RoutedEventArgs e)
 {
     var dialog = new AddOrModifyDevice();
     await DialogHost.Show(dialog, "DeviceDialog");
 }