Convert Datareader to Datatable in asp.net

using System;

using System.Data;

using System.Data.SqlClient;

using System.Data.OleDb;

using System.Configuration;

using System.Web;

using System.Web.Security;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Web.UI.WebControls.WebParts;

using System.Web.UI.HtmlControls;

public partial class _Default : System.Web.UI.Page

{

    IDataAdapter da;

    DataSet ds = new DataSet();

    protected void Page_Load(object sender, EventArgs e)

    {

        DataTable dt = new DataTable();

        dt.Columns.Add("ID", typeof(string));

        dt.Columns.Add("Name", typeof(string));

        dt.Columns.Add("Age", typeof(string));

        dt.Columns.Add("Address", typeof(string));

        DataRow drQuery;

      

      

        da = getReader();

        da.Fill(ds);

        int QCount1 = 0;

        while (QCount1 < ds.Tables[0].Rows.Count)

        {

            drQuery = dt.NewRow();

            drQuery["ID"] = Convert.ToString(ds.Tables[0].Rows[QCount1][1].ToString());

            drQuery["Name"] = ds.Tables[0].Rows[QCount1][3].ToString();

            drQuery["Age"] = ds.Tables[0].Rows[QCount1][2].ToString();

            drQuery["Address"] = ds.Tables[0].Rows[QCount1][9].ToString();

            dt.Rows.Add(drQuery);

            QCount1 = QCount1 + 1;

        }

      

        GridView1.DataSource = dt;

        GridView1.DataBind();

    }

    private IDataAdapter getReader()

    {

     

    

        SqlConnection con = newSqlConnection(ConfigurationManager.ConnectionStrings["testcon"].ToString());

        SqlDataAdapter da = new SqlDataAdapter("select * from t_users",con);

      

        return da;

    }

}