TreeView2.TreeNodeSrc = "GetXml.aspx";

private void SendXml()
        {
            //Create Xml File
            XmlDocument objXmlDoc = new XmlDocument();

            //Insert Xml Declaration
            XmlDeclaration objXmlDeclare = objXmlDoc.CreateXmlDeclaration("1.0", "UTF-8", "yes");
            objXmlDoc.InsertBefore(objXmlDeclare, objXmlDoc.DocumentElement);

            XmlElement objRootElem = objXmlDoc.CreateElement("TREENODES");
            objXmlDoc.AppendChild(objRootElem);

            CreateXml(objXmlDoc, objRootElem, 0);

            System.Xml.XmlTextWriter xmlwriter = new System.Xml.XmlTextWriter(Response.OutputStream,Response.ContentEncoding);
            xmlwriter.Formatting = Formatting.Indented;
            xmlwriter.Indentation = 4;
            xmlwriter.IndentChar = ' ';
            objXmlDoc.WriteTo(xmlwriter);
            xmlwriter.Flush();
            Response.End();
            xmlwriter.Close();
        }

        private void CreateXml(XmlDocument objXMLDoc, XmlElement objRootElem, int belong)
        {
            //Get DataSet
            DataSet ds = new DataSet();
            foreach(DataRow dr in ds.Tables[0].Rows)
            {
                //Create ChildNode TreeNode
                XmlElement objXmlElem = objXMLDoc.CreateElement("TREENODE");
                objRootElem.AppendChild(objXmlElem);

                //Create Attributes Text
                XmlAttribute objXmlAttText = objXMLDoc.CreateAttribute("Text");
                objXmlAttText.Value = dr["text"].ToString().Trim();
                objXmlElem.SetAttributeNode(objXmlAttText);

                //Create Attributes CheckBox
                XmlAttribute objXmlAttCB = objXMLDoc.CreateAttribute("CheckBox");
                objXmlAttCB.Value = "True";
                objXmlElem.SetAttributeNode(objXmlAttCB);

                //Create Attributes Expanded
                XmlAttribute objXmlAttExp = objXMLDoc.CreateAttribute("Expanded");
                objXmlAttExp.Value = "True";
                objXmlElem.SetAttributeNode(objXmlAttExp);

                int id = int.Parse(dr["id"].ToString().Trim());
                CreateXml(objXMLDoc, objXmlElem, id);
            }
        }