CODEWITHSUNDEEP
c#recursion
CodeNinja
CodeNinja

Reputation: 3278

Read all nodes and child nodes recursively

I have an object Node with child Nodes. I would like to read all the Nodes & child nodes and display them into an asp.net dropdown list control.

The node is of type :

Microsoft.TeamFoundataion.WorkItemTracking.Client.Node

The Class Node looks like this :

public class Node
{
    public string Name { get; set; }
    public string Path { get; set; }
}

Each Node has many child nodes & the child nodes have more child nodes and so on....

I have code written to fetch the node & first level of child node. I cannot think how I can recursively read all the nodes ??

Dictionary<string,string> ParentN = new Dictionary<string,string>();
Dictionary<string, string> childN = new Dictionary<string, string>();
foreach (Node area in Proj.Nodes)
{
    ParentN.Add(area.Name, area.Path);
    Console.WriteLine(area.Path);

    foreach (Node item in area.ChildNodes)
    {
        childN.Add(item.Name, item.Path);
        Console.WriteLine(item.Path);
    }
}

Upvotes: 1

Views: 4495

Answers (2)

Vsevolod Goloviznin
Vsevolod Goloviznin

Reputation: 12334

You need a recursive function for that. Children can be parents too. If a child has no children beneath it, then we don't add it to the parents dict.

void GetNode(Node parent)
{
    if (parent.ChildNodes.Any())
    {
        ParentN.Add(parent.Name, parent.Path);
        foreach(child in parent.ChildNodes)
        {
            childN.Add(child.Name, child.Path);
            GetNode(child);
        }
    }
    Console.WriteLine(parent.Name);
}

Upvotes: 4

Ortiga
Ortiga

Reputation: 8824

The class Node you posted does not contain child nodes. I'll assume you meant:

public class Node
{
    public string Name { get; set; }
    public string Path {get; set;}
    IList<Node> ChildNodes { get; set; }
}

You could do it as:

static class NodeExtensions
{
    public static IEnumerable<Node> ReadChildNodes(this Node node)
    {
        foreach(Node childNode in node.ChildNodes){
            if(childNode.ChildNodes != null && childNode.ChildNodes.Any()){
                foreach(Node grandChildren in childNode.ReadChildNodes())
                    yield return grandChildren;
            }

            yield return childNode;
        }
    }
}

Probably this code can be improved, but it works, I guess...

Upvotes: 2

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