treeview问题

Question

ArrayList al;
           GetAllNodeText(treeView1.Nodes);
          private void GetAllNodeText(TreeNodeCollection tn)
          {
           foreach(TreeNode node in tn)
           {
            if(node.Nodes.Count!=0)
            {
             GetAllNodeText(node.Nodes);
            }
            
             al.Add(node.Text);
            }
           }不是高手
凑合看吧