XML File and Dataset.. (Read and Write XML) (Asp.net, C#)

//Read and Write from dataset to XML


using System.Xml.Serialization;
using System.IO;
using System.Data;

 DataSet ds = new DataSet();
 string qry = "Select distinct UserID, UName from dbo.tblUsers";
 ds = AdminBl.Selectrecord("sp_selectglobal", qry); //Executing stored procedure

//writing xml file

 StreamWriter objxml = new StreamWriter(Server.MapPath("~/XMLFile.xml"), false);
        // Apply the WriteXml method to write an XML document
 ds.WriteXml(objxml);
        objxml.Close();

//Read from xml file and Fill the Gridview
  DataSet dset = new DataSet();
        dset .ReadXml(Server.MapPath("~/XMLFile.xml"));
        GridView1.DataSource = dset;
        GridView1.DataBind();