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

Extension method:

public static List GetSelectedItems(this ListBox lst)
{
    return lst.Items.OfType().Where(i => i.Selected).ToList();
}

You can call it on your listbox like:

List selectedItems = myListBox.GetSelectedItems();

You could also do the conversion using a 'Cast' on the list box items like:

return lst.Items.Cast().Where(i => i.Selected).ToList();

Not sure which will perform better OfType or Cast (my hunch is Cast).

Edit based on Ruben's feedback for a generic ListControl method which would indeed make it much more useful extension method:

public static List GetSelectedItems(this ListControl lst)
{
    return lst.Items.OfType().Where(i => i.Selected).ToList();
}