using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.UI; using System.Web.UI.WebControls; using System.Data; using System.Collections; using System.Configuration; using System.Data.SqlClient;   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);                         }                         else                         {                             //查找父节点                             TreeNode ParentNod = (TreeNode)sl.GetByIndex(sl.IndexOfKey(dt.Rows[i]["ParentMenu"].ToString()));                             //创建子节点                             TreeNode tnChild = new TreeNode();                             tnChild.Text = dt.Rows[i]["MenuName"].ToString();                             tnChild.Value = dt.Rows[i]["MenuID"].ToString();                             if (dt.Rows[i]["Flag"].ToString() == "1")                             {                                 tnChild.NavigateUrl = dt.Rows[i]["href"].ToString();                                 tnChild.Target = "_bank";                             }                             tnChild.Expanded = false;                             tnChild.SelectAction = TreeNodeSelectAction.Expand;                             sl.Add(tnChild.Value, tnChild);                             ParentNod.ChildNodes.Add(tnChild);                         }                     }                 }             }             catch (Exception ex)             {                 throw ex;             }         }     } }