private void ClientList_SelectionChanged(object sender, SelectionChangedEventArgs e) { Client selectedClient = ((Client)ClientList.SelectedItem); if (selectedClient == null) { return; } TaxBox.Text = ((Client)ClientList.SelectedItem).FUEL.ToString(); ServiceTaxBox.Text = selectedClient.STAX.ToString(); DiscountBox.Text = selectedClient.AMTDISC.ToString(); BillingDataDataContext db = new BillingDataDataContext(); double prevdue = db.GetPreviousDue(selectedClient.CLCODE) ?? 0; PreviousDueTextBox.Text = prevdue.ToString(); if (SubClientList != null) { SubClientListSource.Source = SubClientList.ContainsKey(selectedClient.CLCODE) ? SubClientList[selectedClient.CLCODE] : new List <string>(); } RefreshDataGridSource(); }