c# - Recursive yield method to traverse object graph and return visited nodes -

i'm trying write extension method supposed traverse object graph , return visited objects.

i'm not sure if approach best, please comment on that. yield frying brain... i'm sure answer obvious :/

model

public class myclass {     public myclass parent {get;set;} } 

method

public static ienumerable<t> selectnested<t>     (this t source, func<t, t> selector)     t : class {     yield return source;     var parent = selector(source);     if (parent == null)         yield break;     yield return selectnestedparents(parent, selector).firstordefault(); } 

usage

var list = myobject.selectnested(x => x.parent); 

the problem

it's working. visits 2 objects. self , parent.

so given graph c -> b -> a starting c. c, b returned not quite wanted.

the result i'm looking b, c

in last line of selectnested return first parent:

yield return selectnestedparents(parent, selector).firstordefault(); 

you have return parents:

foreach (var p in selectnestedparents(parent, selector))   return p; 

instead of using recursion can use iteration more efficient:

public static ienumerable<t> selectnested<t>(this t source, func<t, t> selector)   t : class {   var current = source;   while (current != null) {     yield return current;     current = selector(current);   } }