You can do so as follows:
[C#]
this.myList.SelectedItem = o;
// In case the item is out of view. If so, the next line could cause an exception without bringing this item to view.
myList.ScrollIntoView(this.myList.SelectedItem);
ListViewItem lvi = (ListViewItem)myList.ItemContainerGenerator.ContainerFromIndex(myList.SelectedIndex);
lvi.Focus();