C# 函数方法内部实现循环调用自身

//C# 函数方法内部实现循环调用自身 
void TreeViewFresh(){
    Action<TreeNodeCollection, MenuItem> addNode
　　　　 = (TreeNodeCollection, MenuItem) => { };
    addNode = (tn, mn) =>{
        if (mn.Text != "-"){
            tn.Add(mn.Text, mn.Text);
            if (mn.IsParent)
                foreach (MenuItem mnn in mn.MenuItems)
                    addNode(tn[mn.Text].Nodes, mnn);
        }
    };
    TreeView1.Nodes.Clear();
    foreach (MenuItem mn in mainMenu1.MenuItems)
        addNode(TreeView1.Nodes, mn);
}