求助，treeview绑定数据

Question

现在有teacher和student两个表（一个老师可以带多个老师和多个学生，每个老师和学生只能有一个老师），teacher表有个字段是parentteacherid,student有个字段是teacherid,我想问如何实现一种treeview树形：展开老师节点能显示出这个老师带的老师和学生。各位帮帮忙，最好能给出代码，急用，谢谢

Answer 1

Select * From teacher Left join student
on student.teacherid =teacher. parentteacherid
然后低归这个表

Answer 2

    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();            TreeView tv = new TreeView();
            tv.AfterSelect += new TreeViewEventHandler(tv_AfterSelect);
            tv.Dock = DockStyle.Fill;
            this.BuildTree(tv.Nodes, 0);
            this.Controls.Add(tv);
        }        private void tv_AfterSelect(object sender, TreeViewEventArgs e)
        {
            // 选择节点后，获取当前节点的信息
            // 你可以将下列信息赋给你对应的控件
            DataRow row = (DataRow)e.Node.Tag;            Int32 Id = (Int32)row["Id"];
            Int32 ParentId = (Int32)row["ParentId"];
            String Name = (String)row["Name"];
        }        private DataTable fSampleDataSource;
        public DataTable SampleDataSource
        {
            get
            {
                if (fSampleDataSource == null)
                {
                    // 这里构造一个 DataTable 如果是从数据库获取可以将这部分代码改为从数据获取的代码
                    fSampleDataSource = new DataTable();
                    fSampleDataSource.Columns.Add("Id", typeof(int)); // 节点 ID
                    fSampleDataSource.Columns.Add("ParentId", typeof(int)); // 父节点
                    fSampleDataSource.Columns.Add("Name", typeof(string)); // 节点名称                    fSampleDataSource.Rows.Add(new object[] { 1, 0, "根目录" });
                    fSampleDataSource.Rows.Add(new object[] { 2, 1, "一级目录A" });
                    fSampleDataSource.Rows.Add(new object[] { 3, 1, "一级目录B" });
                    fSampleDataSource.Rows.Add(new object[] { 4, 1, "一级目录C" });                    fSampleDataSource.Rows.Add(new object[] { 5, 2, "二级目录A" });
                    fSampleDataSource.Rows.Add(new object[] { 6, 2, "二级目录B" });
                }                return fSampleDataSource;
            }
        }        /// <summary>
        /// 创建目录和文件树
        /// </summary>
        /// <param name="fNodes"></param>
        /// <param name="fPath"></param>
        public void BuildTree(TreeNodeCollection fNodes, Int32 fParentId)
        {
            foreach (DataRow row
                in this.SampleDataSource.Select(String.Format("ParentId = {0}", fParentId)))
            {
                TreeNode node = new TreeNode();
                node.Text = row["Name"].ToString();
                node.Tag = row;
                // 递归创建子节点
                this.BuildTree(node.Nodes, (Int32)row["Id"]);
                fNodes.Add(node);
            }
        }
    }   
}