/// <summary>
/// Adds a directed edge between the nodes identified by the specified values.
/// </summary>
/// <param name="from">Value identifying the node that will spawn the edge.</param>
/// <param name="to">Value identifying the node on the 'to' end of the edge.</param>
/// <returns>The edge between the targeted nodes.</returns>
public Edge <EdgeListNode <T> > AddDirectedEdge(T from, T to)
{
EdgeListNode <T> fromTarget = FindNode(from);
EdgeListNode <T> toTarget = FindNode(to);
if (fromTarget == null)
{
throw new ArgumentException("The 'from' node is not part of this graph.");
}
if (toTarget == null)
{
throw new ArgumentException("The 'to' node is not part of this graph.");
}
return(fromTarget.AddEdgeTo(to));
}
