LinkedList.AddBefore
using System; using System.Collections; using System.Collections.Generic; using System.Collections.ObjectModel; using System.Text; public class MainClass { public static void Main() { LinkedList<int> list = new LinkedList<int>(); list.AddFirst(10); list.AddLast(15); list.AddLast(3); list.AddLast(99); list.AddBefore(list.Last, 25); LinkedListNode<int> node = list.First; while (node != null) { Console.WriteLine(node.Value); node = node.Next; } } }