private void FillMonth() { try { int loaderHandler = LoadingManager.BeginLoading("Please Wait for pass payment ... "); Cmb_month.Items.Clear(); ReportServiceClient service = new ReportServiceClient(); service.GetMoisAsync(); service.GetMoisCompleted += (er, res) => { try { if (res.Error != null || res.Cancelled) { LoadingManager.EndLoading(loaderHandler); throw new Exception("Cannot display report"); } if (res.Result != null) { var listeMois = res.Result; Cmb_month.ItemsSource = listeMois; Cmb_month.DisplayMemberPath = "LIBELLE"; } } catch (Exception ex) { MessageBox.Show(ex.Message); } finally { LoadingManager.EndLoading(loaderHandler); } }; } catch (Exception ex) { MessageBox.Show(ex.Message); } }