Hierarchical Data In ASP.NET MVC

/// This is the model class
public class MyTreeNode<T>
{
    public ICollection<MyTreeNode> ChildNodes {get;}
    public T MyValue { get; set; }
    bool HasChildren { get { return ChildNodes.Any(); } }
}

///This is the html helper:
public static string RenderTree<T>(this HtmlHelper html, MyTreeNode<T> root, Func<T, string> renderNode)
{
    var sb = new StringBuilder();
    sb.Append(renderNode(root.MyValue));
    if (root.HasChildren)
    {
        foreach(var child in root.ChildNodes)
        {
            sb.Append(RenderTree<T>(html, child, renderNode));
        }
    }
    return sb.ToString();
}