retrieving id and name for already login user using sessions

on page load
// string name = Session["nameforlogin"].ToString();
           // string id = Session["id"].ToString();

on button click
 SqlConnection conn = new SqlConnection();
            conn.ConnectionString="Data Source=USER-PC\\ADITYA;Initial Catalog=holder;Persist Security Info=True;User ID=sa;Password=123";
            conn.Open();
            SqlCommand cmd = new SqlCommand();
            cmd.Connection = conn;
            cmd.CommandText = "insert into tb_userdata (employeeidfromtable1,Name,dicription,aboutme)  values ('" +( Session["id"]) + "','" + Session["name"] + "','" +txtdesr.Text + "','"+txturl .Text+"');";
            cmd.ExecuteNonQuery();
            conn.Close();