how can public function is convert to session

Question

private void GetMenuData()
  {
  try
  {
  string meanu_id = "", a = "";
  SqlParameter[] paramater1 = new SqlParameter[]
  { 
  new SqlParameter("@Branch",1),
  new SqlParameter("@Users",1),
  };
  SqlDataReader dr = (SqlDataReader)db.ExecuteReader("GetRoll_ForMeanu", paramater1);
  if (dr.HasRows)
  {
  dr.Read();
  meanu_id = dr["Menu_Id"].ToString();
  a = dr["Role"].ToString();
  }
  dr.Close();
  DataTable dt = new DataTable();
  // dt = (DataTable)db.TableFill1("MenuMaster_SelectQuery");
  dt = (DataTable)db.Meanu_Fill("SELECT menu_id, menu_name, menu_parent_id, menu_url, Target FROM MenuMaster where menu_id in(" + meanu_id + ") Order By menu_id");
  DataView view = new DataView(dt);
  view.RowFilter = "menu_parent_id is NULL";
  foreach (DataRowView row in view)
  {
  MenuItem menuItem = new MenuItem(row["menu_name"].ToString(), row["menu_id"].ToString());
  menuItem.NavigateUrl = row["menu_url"].ToString();
  Menu1.Items.Add(menuItem);
  AddChildItems(dt, menuItem);
  //Session["menu"] = menuItem;
  } 
  }
  catch (Exception ex)
  {
  db.MessageBox(ex.Message, this);
  }
  }
  private void AddChildItems(DataTable table, MenuItem menuItem)
  {
  DataView viewItem = new DataView(table);
  viewItem.RowFilter = "menu_parent_id=" + menuItem.Value;
  foreach (DataRowView childView in viewItem)
  {
  MenuItem childItem = new MenuItem(childView["menu_name"].ToString(), childView["menu_id"].ToString());
  childItem.NavigateUrl = childView["menu_url"].ToString();
  childItem.Target = childView["Target"].ToString();
  menuItem.ChildItems.Add(childItem);
  AddChildItems(table, childItem);
  }
  }
sir this is my function how to convert



Session["GetMenuData"]= GetMenuData();