using System;using System.Collections.Generic;using System.ComponentModel;using System.Data;using System.Drawing;using System.Linq;using System.Text;using System.Windows.Forms;namespace TreeView{    public partial class FrmTreeView : Form    {        bool isShow = false;        public FrmTreeView()        {            InitializeComponent();            tvTree.Nodes.Add("湖南省");        }        private void tsmShowAdd_Click(object sender, EventArgs e)        {            if (!isShow)            {                DataSet ds = DatabaseHelper.GetDataSet();                AddTreeNode(ds, "cf0dbde5-14d6-44be-9f71-4e5d302afc99", tvTree.TopNode);                isShow = true;            }                   }        private void AddTreeNode(DataSet ds,string fatherKey,TreeNode Nodes)        {            var results = from result in ds.Tables[0].AsEnumerable()                           where result.Field<string>("SYS_FATHERKEY") == fatherKey                           select result;            foreach (var item in results)            {                TreeNode node = new TreeNode();                node.Text = item.Field<string>("SYS_NAME");                                if (Nodes == null)                {                    tvTree.Nodes.Add(Nodes);                }                else                {                    Nodes.Nodes.Add(node);                }                AddTreeNode(ds, item.Field<string>("SYS_KEY"),node);            }        }    }}