private void MAddUserKeysButton_Click(object sender, RoutedEventArgs e)
{
ShowKeys w = new ShowKeys();
w.Closed += (s, args) => viewModel.PerformValidation();
w.Show();
}
private void MShowKeysButton_Click(object sender, RoutedEventArgs e)
{
var window = new ShowKeys();
window.Closed += (o, ev) => this.viewModel.PerformValidation();
window.Show();
}