C# TreeView读取数据库简单实例

效果：

数据库：

思路：

利用for遍历，然后创建父节点，再根据父节点创建出子节点。

代码：

namespace TreeView
{
    public partial class TreeView : System.Web.UI.Page
    {
        string connection = ConfigurationManager.ConnectionStrings["SQLconnection"].ToString();
        protected void Page_Load(object sender, EventArgs e)
        {
            select();
            CreateTree();
        }
        DataSet ds = new DataSet();
        public DataSet DataS(string sql, string tablename)
        {
            SqlConnection con = new SqlConnection(connection);
            SqlDataAdapter sqlda = new SqlDataAdapter(sql, con);
            sqlda.Fill(ds, tablename);
            return ds;
        }

        //ParentMenu:父节点,
        //Grade:标识这是第几级节点,
        //Flag:标识是不是尾结点，1是 0 不是,
        //href:指向的链接
        public void select()
        {
            string sql = "select * from treeview";
            ds = DataS(sql, "test");
        }

        public void CreateTree()
        {
            try
            {
                DataTable dt = ds.Tables["test"];
                SortedList sl = new SortedList();
                TreeNode tn = new TreeNode();
                if (dt.Rows.Count <= 0)
                {
                    tn.Text = "空";
                    tn.Value = "";
                    tn.NavigateUrl = "";
                    tn.Target = "";
                    tn.Expanded = false;
                    tn.SelectAction = TreeNodeSelectAction.SelectExpand;

                }
                else
                {
                    for (int i = 0; i < dt.Rows.Count; i++)
                    {
                        //创建父节点
                        if (dt.Rows[i]["Grade"].ToString() == "1")
                        {
                            TreeNode node = new TreeNode();
                            node.Text = dt.Rows[i]["MenuName"].ToString();
                            node.Value = dt.Rows[i]["MenuID"].ToString();
                            if (dt.Rows[i]["Flag"].ToString() == "1")
                            {
                                node.NavigateUrl = dt.Rows[i]["href"].ToString();
                                tn.Target = "_bank";
                            }
                            node.Expanded = false;
                            node.SelectAction = TreeNodeSelectAction.Expand;
                            sl.Add(node.Value, node);
                            tv_Method.Nodes.Add(node);
               &n