Bind Gridview from Session , Then Edit, Update, Delete the gridview

using System;
using System.Data;
using System.Configuration;
using System.Collections;
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;

namespace WebApplication1
{
    public partial class WebForm1 : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
           TextBox1.Text = "";
           TextBox2.Text = "";
        }

        protected void Button2_Click(object sender, EventArgs e)
        {// ADDED DATA TO THE TEXT BOX AND CLICKED ON ADD BUTTON
        AddNewData();
        }

        protected void Button1_Click(object sender, EventArgs e)
        {// GOING TO ANOTHER FORM TO DISPLAY THE DATA
            Response.Redirect("Default.aspx");
        }
        public void AddNewData()
        {// ADDING DATA AND STORING THE DATATABLE INTO THE SESSION
            DataTable dt = new DataTable();

            if (Session["myDatatable"] != null)
            {
                dt = (DataTable)Session["myDatatable"];
            }
            else
            {
                dt.Columns.Add("Name");
                dt.Columns.Add("ID");
            }

            DataRow drow = dt.NewRow();

            drow["Name"] = TextBox2.Text.ToString();
            drow["ID"] = TextBox1.Text.ToString();

            dt.Rows.Add(drow);

            Session["myDatatable"] = dt;
            TextBox1.Text = "";
            TextBox2.Text = "";
        }

    }
}

using System;
using System.Data;
using System.Configuration;
using System.Collections;
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;

namespace WebApplication1
{
    public partial class _Default : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            if (!IsPostBack)
            {
                BindMyGridview();
            }
        }

        protected void Button1_Click(object sender, EventArgs e)
        {// CLICKED ON THE BUTTON TO GO TO THE PAGE WITH TEXTBOXES TO ADD NEW DATA
            Response.Redirect("Webform1.aspx");
        }

        public void BindMyGridview()
        {// BINDING THE Gridview1 FROM SESSION
            if (Session["myDatatable"] != null)
            {
                DataTable dt = (DataTable)Session["myDatatable"];

                if ((dt != null) && (dt.Rows.Count > 0))
                {
                    GridView1.Visible = true;
                    GridView1.DataSource = dt;
                    GridView1.DataBind();
                }
                else
                {
                    GridView1.Visible = false;
                }
            }

        }


        protected void GridView1_RowEditing(object sender, GridViewEditEventArgs e)
        {// Gridview1's RowEditing Event
            GridView1.EditIndex = e.NewEditIndex;
            BindMyGridview();
        }

        protected void GridView1_RowUpdating(object sender, GridViewUpdateEventArgs e)
        {// Gridview1's RowUpdating Event

            TextBox TextBoxWithID = (TextBox)GridView1.Rows[e.RowIndex].FindControl("TextBox2");
            TextBox TextBoxWithName = (TextBox)GridView1.Rows[e.RowIndex].FindControl("TextBox4");
            string NewID = TextBoxWithID.Text.ToString();
            string NewName = TextBoxWithName.Text.ToString();

            DataTable dt = (DataTable)Session["myDatatable"];

            DataRow dr = dt.Rows[e.RowIndex];

            dr["ID"] = NewID;
            dr["Name"] = NewName;
            dr.AcceptChanges();
            Session["myDatatable"] = dt;

            GridView1.EditIndex = -1;
            BindMyGridview();

        }

        protected void GridView1_RowCancelingEdit(object sender, GridViewCancelEditEventArgs e)
        {// Gridview1's RowEditing Cancel Event
            GridView1.EditIndex = -1;
            BindMyGridview();
        }

       protected void GridView1_RowDeleting(object sender, GridViewDeleteEventArgs e)
        {// Gridview1's RowDeleting Event
            DataTable dt = (DataTable)Session["myDatatable"];

            DataRow dr = dt.Rows[e.RowIndex];

            dt.Rows.Remove(dr);

            GridView1.EditIndex = -1;
            BindMyGridview();
        }
    }
}