private void ClickAddSoftware(object sender, RoutedEventArgs e)
        {
            AddSoftware addpc = new AddSoftware();

            if (addpc.ShowDialog() == true)
            {
                software.Add(addpc.software);
            }
        }
        private void ClickUpdateSoftware(object sender, RoutedEventArgs e)
        {
            var sel = SoftwareListView.SelectedItems;

            foreach (var item in sel)
            {
                AddSoftware addpc = new AddSoftware(item as Software);
                addpc.ShowDialog();
            }
            SoftwareListView.ItemsSource = null;
            SoftwareListView.ItemsSource = software;
        }