Здравствуйте, Sinclair, Вы писали:
S>попытка 2:
S>S>var node1 = new Node("Hello") { Next = null!, Previous = null! };
S>var node2 = new Node("World") { Next = node1, Previous = node1) };
S>node1.Previous = node2;
S>foreach(var n in Iterate(node1)
S> Console.WriteLine(n);
S>
S>Unhandled exception. System.NullReferenceException: Object reference not set to an instance of an object.
S>Попробуйте решить проблему при помощи EmptyNode.
var node1 = new Node("Hello") { Next = Node.EmptyNode, Previous = Node.EmptyNode };
var node2 = new Node("World") { Next = node1, Previous = Node.EmptyNode) };
node1.Previous = node2;
foreach(var n in Iterate(node1)
Console.WriteLine(n);
И никаких System.NullReferenceException
