Enumerating Collections that are not inherently IEnumerable?

Question

When you want to recursively enumerate a hierarchical object, selecting some elements based on some criteria, there are numerous examples of techniques like \"flattening\" a

Answer 1

I guess you are asking for something like this.

public static IEnumerable  GetNodesRecursively(this TCollection nodeCollection, Func getSub)
 where T, TCollection: IEnumerable
{   
    foreach (var theNode in )
    {
        yield return theNode;
        foreach (var subNode in GetNodesRecursively(theNode, getSub))
        {
            yield return subNode;
        }
    }
}

var all_control = GetNodesRecursively(control, c=>c.Controls).ToList();