private void OnUserAutoCompleteBoxPopulating(object sender, PopulatingEventArgs e) { var acb = sender as AutoCompleteBox; if (acb != null) { var context = new SystemUserDomainContext(); context.SearchUser(e.Parameter, (obj) => { if (Utility.Utility.CheckInvokeOperation(obj)) { acb.ItemsSource = obj.Value; } }, null); } }