最近研究了一下treeview，發(fā)現(xiàn)有兩種實(shí)現(xiàn)無(wú)限級(jí)樹(shù)的方法，文字不想多寫(xiě)，直入主題。

先看看效果圖：

先看看數(shù)據(jù)庫(kù)表的設(shè)計(jì)，數(shù)據(jù)表主要包括ID，Name，ParentID這三項(xiàng)，其中ID是主鍵，ParentID對(duì)應(yīng)節(jié)點(diǎn)的父節(jié)點(diǎn)：

方法一：用遞歸遍歷數(shù)據(jù)，并將節(jié)點(diǎn)逐個(gè)添加到treeview中去。

1.先進(jìn)行數(shù)據(jù)庫(kù)連接和數(shù)據(jù)的讀取，并將根節(jié)點(diǎn)先添加進(jìn)treeview中，并利用遞歸getTreeView（）實(shí)現(xiàn)數(shù)據(jù)的遍歷和添加：

 protected void Page_Load(object sender, EventArgs e)
        {
           
            if (!Page.IsPostBack)
            {
                TreeNode nodeCategory ;
                connection conn = new connection();
                List<Category> category = conn.getCategory();
                Stack<Category> storeCategory = new Stack<Category>();
                storeCategory.Push(category[0]);
                nodeCategory = new TreeNode(category[0].Name.Trim(), category[0].Id.Trim());
                TreeView1.Nodes.Add(nodeCategory);
                getTreeView(storeCategory, category, nodeCategory);
                               
            }
        }

2.數(shù)據(jù)遍歷的遞歸函數(shù)，比較簡(jiǎn)單就不多說(shuō)了。

 public void getTreeView(Stack<Category> categoryStack,List<Category> categoryList,TreeNode e)
        {
            Category tmp;
            if(categoryStack.Count>0)
            {
                tmp=categoryStack.Pop();
                for(int i=0;i<categoryList.Count;i++)
                    if(categoryList[i].ParentId.Trim()==tmp.Id.Trim())
                    {
                        categoryStack.Push(categoryList[i]);
                        TreeNode childNote = new TreeNode(categoryList[i].Name.Trim(), categoryList[i].Id.Trim());
                        e.ChildNodes.Add(childNote);
                        getTreeView(categoryStack, categoryList, childNote);
                    }
            }
        }

方法二：用TreeView1_TreeNodePopulate(object sender, TreeNodeEventArgs e)事件響應(yīng)來(lái)逐個(gè)讀取子節(jié)點(diǎn)。

1.第一步基本和上一方法的第一步一致，只是要將節(jié)點(diǎn)的設(shè)置為不展開(kāi)。

protected void Page_Load(object sender, EventArgs e)
        {
           
            if (!Page.IsPostBack)
            {
                TreeNode nodeCategory ;
                connection conn = new connection();
                List<Category> category = conn.getCategory();
                nodeCategory = new TreeNode(category[0].Name.Trim(), category[0].Id.Trim());
                nodeCategory.PopulateOnDemand = true;
                nodeCategory.Collapse();
                nodeCategory.NavigateUrl = "http://blog.csdn.net/longlongago2000";
                nodeCategory.Target = "_blank";
                TreeView1.Nodes.Add(nodeCategory);
             }
        }

2.再改寫(xiě)TreeView1_TreeNodePopulate（），根據(jù)鼠標(biāo)的點(diǎn)擊得到該節(jié)點(diǎn)的ID，然后根據(jù)該ID進(jìn)行數(shù)據(jù)的讀取，將其下的子節(jié)點(diǎn)讀出。

protected void TreeView1_TreeNodePopulate(object sender, TreeNodeEventArgs e)
        {

            int categoryID = Int32.Parse(e.Node.Value);
            connection conn = new connection();
            List<Category> category = conn.getCategory();
            foreach (Category tmp in category)
            {
                if (categoryID.ToString() == tmp.ParentId.Trim())
                {
                    TreeNode childNote = new TreeNode(tmp.Name.Trim(), tmp.Id.Trim());

                    foreach (Category cate in category)
                    {
                        if (tmp.Id.Trim() == cate.ParentId.Trim())
                        {
                            childNote.PopulateOnDemand = true;

                            childNote.Collapse();
                            break;

                        }
                        else
                            childNote.Expand();
                    }

                    childNote.NavigateUrl ="http://blog.csdn.net/longlongago2000" ;
                    childNote.Target = "_blank";
                    e.Node.ChildNodes.Add(childNote);
                }
            }
以上兩種方法都可以實(shí)現(xiàn)無(wú)限級(jí)分類(lèi)，不過(guò)第一種方法顯然更好一些，第二種方法不可以實(shí)現(xiàn)全部展開(kāi)功能，而第一種可以。

以上原創(chuàng)，本人博客地址：http://blog.csdn.net/longlongago2000

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