TreeView控件可以通过递归方式绑定数据库数据，代码如下：

    void Page_Load()

    {

        if (!Page.IsPostBack)

            PopulateTreeView();

    }

    private void PopulateTreeView()

    {

        DataTable treeViewData = GetTreeViewData();

        AddTopTreeViewNodes(treeViewData);  //绑定父节点

    }

    private DataTable GetTreeViewData()    //获取数据

    {

        string selectCommand = "SELECT MessageId,ParentId,Subject FROM Discuss";

        string conString = WebConfigurationManager.ConnectionStrings["Discuss"].ConnectionString;

        SqlDataAdapter dad = new SqlDataAdapter(selectCommand, conString);

        DataTable dtblDiscuss = new DataTable();

        dad.Fill(dtblDiscuss);

        return dtblDiscuss;

    }

    private void AddTopTreeViewNodes(DataTable treeViewData)

    {

        DataView view = new DataView(treeViewData);

        view.RowFilter = "ParentID IS NULL";

        foreach (DataRowView row in view)

        {

            TreeNode newNode = new TreeNode(row["Subject"].ToString(), row["MessageId"].ToString());

            TreeView1.Nodes.Add(newNode);

            AddChildTreeViewNodes(treeViewData, newNode);//绑定子节点

        }

    }

    private void AddChildTreeViewNodes(DataTable treeViewData, TreeNode parentTreeViewNode)

    {

        DataView view = new DataView(treeViewData);

        view.RowFilter = "ParentID=" + parentTreeViewNode.Value;

        foreach (DataRowView row in view)

        {

            TreeNode newNode = new TreeNode(row["Subject"].ToString(), row["MessageId"].ToString());

            parentTreeViewNode.ChildNodes.Add(newNode);

            AddChildTreeViewNodes(treeViewData, newNode);//递归，绑定子节点

        }

    }

数据表中记录通过ParentId字段指定父节点。

详细介绍可以参考：《ASP.NET2.0揭秘卷1》

 树节点TreeNode的重要属性：

Text：节点显示内容

Value：节点对应值

NavigateUrl：导航页面Url

Target：目标框架

ImageUrl：节点图像