以前写了编关于无限级分类的文章，但主要是用于Windows编程上用的，因为与treeView控件相结合。参考：
blog.csdn.net/dhlhh/archive/2004/10/13/134438.aspx
修正程序：
blog.csdn.net/dhlhh/archive/2004/10/15/138105.aspx

这次因要用到ASP.net上编程，所以以上方法有些不同了。原打算用数据结构写一个类，但觉太烦，递归编程不一定效率很高，所以从另一个角度编程，比较适合网络程序，不过也能用在WINDOWS上，只是样子不太好看。WEB中主要用于后台管理。

类的调试是在WINDOWS FORM上，如下样式

图片如下：

下面的TreeList类是关键的类，它的方法主要是用一数组存放Node，并在添加中判断插入数组的位置、缩进，并动态添加路径。路径很重要，特别是IDPath，可用于以后的搜索、插入等。

IDPath的增加方法，是在找到父节点后，路径为父类的路径+自身ID

    public class TreeList
    {
        private ArrayList mNodes;    // Node集合

        public ArrayList Nodes
        {
            get
            {
                return mNodes;
            }
        }

        public TreeList()
        {

        }

        /// <summary>
        /// 添加一个节点
        /// </summary>
        public bool AddNode(Node node)
        {
            // 空节点不添加
            if (node == null)
            {
                return false;
            }

            if (mNodes.Count == 0)
            {
                // 添加根节点
                if (node.ID == 0)
                {
                    node.ParentID = 0;    
                    node.Name = "";
                    node.NamePath = "root";
                    node.IDPath = "0";
                    node.Index = 1;
                    node.Indent = -1;

                    mNodes.Add((object)node);

                    return true;
                }
                else
                {
                    return false;
                }
            }
            else
            {
                bool nodeFound = false;
                Node pNode;
                int iPosition = 0;        // 插入点位置

                for (int ndIndex = (mNodes.Count - 1); ndIndex >= 0; ndIndex--)
                {
                    pNode = (Node)mNodes[ndIndex];

                    // 如果找到Node的ID与添加Node的父类ID号相同
                    if ( pNode.ID == node.ParentID )
                    {
                        nodeFound = true;

                        node.NamePath = pNode.NamePath + "\\" + node.Name;
                        node.IDPath = pNode.IDPath + "\\" + node.ID.ToString();
                        node.Indent = pNode.Indent + 1;

                        iPosition = ndIndex + 1;

                        // 查找序号比它大的节点
                        for ( int i = iPosition; i < mNodes.Count; i++ )
                        {
                            if ( ((Node)mNodes[i]).IDPath.IndexOf(pNode.IDPath) != 0 )
                            {
                                break;
                            }
                            else
                            {
                                if ( ((Node)mNodes[i]).ParentID == node.ParentID)                                    
                                {
                                    if ( ((Node)mNodes[i]).Index > node.Index )
                                    {
                                        iPosition = i;
                                        break;
                                    }
                                    else
                                    {
                                        iPosition = i+1;
                                    }
                                }
                                else
                                {
                                    iPosition = i + 1;
                                }
                            }
                        }

                        // 把节点插入到数组
                        mNodes.Insert(iPosition, (object)node);
                        return true;
                    }
                }

                if (!nodeFound) return false;
            }

            return false;
        }

        /// <summary>
        /// 重置树
        /// </summary>
        public void ResetTreeList(ArrayList srcNodes)
        {
            mNodes = new ArrayList();

            Node node = new Node();
            AddNode(node);

            while (srcNodes.Count > 0)
            {
                for (int i = 0; i < srcNodes.Count; i++)
                {
                    if (AddNode((Node)srcNodes[i]))
                    {
                        srcNodes.RemoveAt(i);
                        break;
                    }
                }
            }
        }
    }

好贴，学习一下！