when am inserting 2nd record lossing previous recods any one tel me how can i see all records

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;

public partial class Default2 : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {


    }

    protected void btnsave_Click(object sender, EventArgs e)
    {
        DataTable dt = new DataTable();
        if (Session["CurrentData"] != null)
        {
            dt = (DataTable)Session["CurrentData"];
        }
        DataRow dr;

        dt.Columns.Add(new System.Data.DataColumn("Name", typeof(String)));
        dt.Columns.Add(new System.Data.DataColumn("Address", typeof(String)));
        dt.Columns.Add(new System.Data.DataColumn("Cell", typeof(String)));



        dr = dt.NewRow();

        dr[0] = TextBox1.Text;
        dr[1] = TextBox2.Text;
        dr[2] = TextBox3.Text;
        dt.Rows.Add(dr);

        Session["CurrentData"] = dt;

        clearfields();


    }
    protected void Button1_Click(object sender, EventArgs e)
    {
        Response.Redirect("Default3.aspx");

    }
    private void clearfields()
    {
        TextBox1.Text = "";
        TextBox2.Text = "";
        TextBox3.Text = "";


    }
}

private DataTable CreatEmptyDT()
{
    DataTable dt = new DataTable();

    dt.Columns.Add(new System.Data.DataColumn("Name", typeof(String)));
    dt.Columns.Add(new System.Data.DataColumn("Address", typeof(String)));
    dt.Columns.Add(new System.Data.DataColumn("Cell", typeof(String)));

    return dt;
}

public DataTable CurrentData
{
    get
    {
        object o = Session["CurrentData"];
        if (o == null)
            return CreatEmptyDT();
        else
            return (DataTable)o;
    }
    set { Session["CurrentData"] = value; }
}

protected void btnsave_Click(object sender, EventArgs e)
{
    DataTable dt = CurrentData;

    DataRow dr = dt.NewRow();

    dr[0] = TextBox1.Text;
    dr[1] = TextBox2.Text;
    dr[2] = TextBox3.Text;
    dt.Rows.Add(dr);

    CurrentData = dt;

    clearfields();
}