private void DeleteCustomersButton_OnClick(object sender, RoutedEventArgs e) { IList selectedCustomers = CustomersDataGrid.SelectedItems; int customersSize = selectedCustomers.Count; for (var i = 0; i < customersSize; i++) { DataRowView row = (DataRowView)CustomersDataGrid.SelectedItems[i]; string textId = row["Id"].ToString(); int id = Convert.ToInt32(textId); _client.DeleteClient(id); } CustomersTabItem_OnLoaded(sender, e); }