Get all selected items from asp.net ListBox

Question

Anyone know of a smooth way to get all of the selected items in a listbox control by using extension methods?

And, please, spare me the argument of

Answer 1

var selected = yourListBox.Items.GetSelectedItems();
//var selected = yourDropDownList.Items.GetSelectedItems();
//var selected = yourCheckBoxList.Items.GetSelectedItems();
//var selected = yourRadioButtonList.Items.GetSelectedItems();

public static class Extensions
{
    public static IEnumerable GetSelectedItems(
           this ListItemCollection items)
    {
        return items.OfType().Where(item => item.Selected);
    }
}