I'm trying to get the selected items from ListView (WPF System.Windows.Controls.ListView) and pass it to another variable to store choice but I get a NullReferenceException.

```
List<LViewItem> onlySelectedItems = null;
var selectedItems = listView1.SelectedItems;

foreach (var item in selectedItems)
{
    onlySelectedItems.Add((LViewItem)item);  // Throws NullReferenceException
}

```

How can I save the selected items to another variable to store choice?