private void ShowCalculator_Click(object sender, RoutedEventArgs e)
{
var view = new CalculatorView();
view.Owner = Application.Current.MainWindow;
view.Show();
}
private void Application_Startup(object sender, StartupEventArgs e)
{
CalculatorView view = new CalculatorView();
view.DataContext = new CalculatorViewModel();
view.Show();
}