gistfile1.cs

public class NodeCollection : Dictionary<string, Node>
{
    public NodeCollection Add(params string[] names)
    {
        foreach (string name in names)
        {
            this[name] = new Node(name);
        }
        return this;
    }

    public NodeCollection Link(params string[] links)
    {
        foreach (string link in links)
        {
            string[] n = link.Split(',');
            this[n[0]].Neighbors.Add(this[n[1]]);
            this[n[1]].Neighbors.Add(this[n[0]]);
        }
        return this;
    }
}