TreeView in asp.net : How to insert two column in child nodes in treeview

+ Parent Node
         - Child Node [Text] [Button]
         - Child Node [Text1] [Button1]
         - Child Node [Text2] [Button2]

TreeView1.Nodes.Clear();

         if (dtTree != null)
        {
            // Create DataRelation.................
            DataRelation rel = new DataRelation("ClientCategory", dtTree.Tables[0].Columns["TPAClientGroupId"],
            dtTree.Tables[1].Columns["TPAClientGroupId"], false);
            rel.Nested = true;

            dtTree.Relations.Add(rel);
             // Set the Attribute here .........................
            foreach (DataColumn dc in dtTree.Tables[0].Columns)
            {
                dc.ColumnMapping = MappingType.Attribute;
            }
            foreach (DataColumn dc in dtTree.Tables[1].Columns)
            {
                dc.ColumnMapping = MappingType.Attribute;
            }

           // xml decleartion ......................................
            XmlDataSource xmlD = new System.Web.UI.WebControls.XmlDataSource();


            xmlD.ID = "XmlDataSource1";
            // Call GetXml and assign to xml data source.
            XmlDataSource1.Data = dtTree.GetXml();


        }