How to update mutiple data into sql server

I am doing system using window phone 7 and sql server as database.
I am using below coding to get shopping cart list at listbox.

public List<Order> FindOrder(string custemail, string orderstatus) {    var findorder = from r in order.Orders                     where (r.CustEmail  == custemail && r.OrderStatus == orderstatus )                     select r;    return findorder.ToList(); }  public pgShopCart() {         var obj = App.Current as App;     custemail = obj.custEMAIL;     string orderstatus = "Pending";     proxy.FindOrderCompleted += new EventHandler<FindOrderCompletedEventArgs>(proxy_FindOrderCompleted);     proxy.FindOrderAsync(custemail, orderstatus); }  void proxy_FindOrderCompleted(object sender, FindOrderCompletedEventArgs e) {     ListBox1.ItemsSource = e.Result; }

After that I want to update the orderId status become "success" but I am only able to update 1 row only by using assign listbox1.itemsource into observable collection.

void proxy_FindOrderCompleted(object sender, FindOrderCompletedEventArgs e) {     ListBox1.ItemsSource = e.Result;     ObservableCollection<Order> Orders = this.ListBox1.ItemsSource as ObservableCollection<Order>;      foreach (Order order in Orders)     {         orderid = order.OrderID;     }  }

and this to update row:

public void UpdateOrderStatus(int orderid, string orderstatus, string paymentdate) {     Order data = order.Orders.Single(p => p.OrderID == orderid);     data.OrderStatus = orderstatus;     order.SubmitChanges(); }  private void btnPay_Click(object sender, RoutedEventArgs e) {     proxy.UpdateOrderStatusCompleted += new EventHandler<UpdateOrderStatusCompletedEventArgs>(proxy_UpdateOrderStatusCompleted);     proxy.UpdateOrderStatusAsync(orderid, orderstatus); }

Any idea to edit my coding for update multiple rows into database?