Web service for news update using sql database

this code will generate XML file for the database entry which will useful to access in web application
steps:
Import following namespace
using System.Xml;
using System.Data.Sql;

[WebMethod]
    public XmlElement GetUserDetails(string str1)
    {
        con = new SqlConnection(ConfigurationManager.ConnectionStrings["NewsConnection"].ToString());
        con.Open();
        cmd = new SqlCommand("select * from NewsData where NewsCategory like @str1 + '%'", con);
       // dr = cmd.ExecuteReader();
       // cmd.Parameters.AddWithValue("@News", NewsHeadline);
        cmd.Parameters.AddWithValue("@str1", str1);
        cmd.ExecuteNonQuery();
        SqlDataAdapter da = new SqlDataAdapter(cmd);
        // Create an instance of DataSet.
        DataSet ds = new DataSet();
        da.Fill(ds);
        con.Close();
        // Return the DataSet as an XmlElement.
        XmlDataDocument xmldata = new XmlDataDocument(ds);
        XmlElement xmlElement = xmldata.DocumentElement;
        return xmlElement;
    }
}