<asp:TreeView id="SampleTreeView" DataSourceID="SampleDataSource" runat="server">
         
<DataBindings>
<asp:TreeNodeBinding DataMember="Node1" TextField="Attribute1" SelectAction="SelectExpand" />
<asp:TreeNodeBinding DataMember="Node2" TextField="Attribute2" SelectAction="SelectExpand" />
</DataBindings>
         
</asp:TreeView>

<asp:XmlDataSource id="SampleDataSource" DataFile="Sample.xml" runat="server" />

public partial class TreeView : System.Web.UI.Page
{
protected override void OnInit(EventArgs e)
{
base.OnInit(e);
treeMap.SelectedNodeChanged += new EventHandler(TreeView1_SelectedNodeChanged);
}
void TreeView1_SelectedNodeChanged(object sender, EventArgs e)
{
string s = treeMap.SelectedNode.Text;
}
}

<asp:TreeView ID="treeMap" runat="server" DataSourceID="siteMap">
<DataBindings>
<asp:TreeNodeBinding DataMember="SiteMapNode" SelectAction="SelectExpand" TextField="title" ValueField="url"  />
</DataBindings>
</asp:TreeView>
<asp:SiteMapDataSource ID="siteMap" runat="server" />